Apparatus and method for IoT control channel

ABSTRACT

Embodiments described herein include user equipment (UE), evolved node B (eNB), methods, and systems for narrowband Internet-of-Things (IoT) communications. Some embodiments particularly relate to control channel communications between UE and eNB in narrowband IoT communications. In one embodiment, a UE blind decodes a first control transmission from an evolved node B (eNB) by processing a first physical resource block comprising all subcarriers of the transmission bandwidth and all orthogonal frequency division multiplexed symbols of a first subframe to determine the first control transmission. In various further embodiments, various resource groupings of resource elements are used as part of the control communications.

PRIORITY CLAIM

This application is a continuation of U.S. patent application Ser. No.16/068,882, titled “Apparatus and Method for IOT Control Channel”, filedJul. 9, 2018, which is a U.S. National Stage Filing under 35 U.S.C. 371from International Application No. PCT/US2016/053759, filed Sep. 26,2016 and published in English as WO 2017/123286 on Jul. 20, 2017, whichclaims the benefit of priority to U.S. Provisional Patent ApplicationSer. No. 62/277,401, filed Jan. 11, 2016, and entitled “CONTROL CHANNELTRANSMISSION FOR NARROWBAND INTERNET-OF-THINGS SYSTEMS,” each of whichis incorporated herein by reference in its entirety. The claims in theinstant application are different than those of the parent applicationand/or other related applications. The Applicant therefore rescinds anydisclaimer of claim scope made in the parent application and/or anypredecessor application in relation to the instant application. Any suchprevious disclaimer and the cited references that it was made to avoid,may need to be revisited. Further, any disclaimer made in the instantapplication should not be read into or against the parent applicationand/or other related applications.

TECHNICAL FIELD

Embodiments pertain to radio access networks. Some embodiments relate toproviding data in cellular and wireless local area network (WLAN)networks, including Third Generation Partnership Project Long TermEvolution (3GPP LTE) networks and LTE advanced (LTE-A) networks as wellas 4^(th) generation (4G) networks and 5^(th) generation (5G) networks,all of which are hereinafter referred to as LTE networks. Someembodiments particularly relate to narrowband internet-of-things (IoT)systems.

BACKGROUND

The use of 3GPP LTE systems (including LTE and LTE-Advanced systems) hasincreased due to an increase in both the types of user equipment (UEs)using network resources and the amount of data and bandwidth being usedby various applications, such as video streaming, operating on theseUEs. As a result, 3GPP LTE systems continue to develop, with thenext-generation wireless communication system, 5G, aiming to answer theever-increasing demand for bandwidth.

In particular, machine-type communications (MTC) include differentresource demands than other types of systems, and therefore networkcommunications structured for IoT systems may drive demand for newnetwork communication structures.

BRIEF DESCRIPTION OF THE FIGURES

In the figures, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The figures illustrate generally, by way of example, but notby way of limitation, various embodiments discussed in the presentdocument.

FIG. 1 is a functional diagram of a wireless network, in accordance withsome embodiments.

FIG. 2 illustrates components of a communication network, in accordancewith some embodiments.

FIG. 3 illustrates a method for control channel communications in anarrowband (NB-IoT) system, in accordance with embodiments describedherein.

FIG. 4 illustrates a method for control channel communications in aNB-IoT system, in accordance with embodiments described herein.

FIG. 5 illustrates a method for control channel communications in aNB-IoT system, in accordance with embodiments described herein.

FIG. 6 illustrates aspects of a UE, in accordance with some exampleembodiments.

FIG. 7 is a block diagram illustrating an example computer systemmachine which may be used in association with various embodimentsdescribed herein.

FIG. 8 illustrates aspects of a UE, in accordance with some exampleembodiments.

DETAILED DESCRIPTION

Embodiments pertain to radio access networks. Some embodiments relate toproviding data in cellular and WLAN networks, including 3GPP LTEnetworks and LTE-A networks as well as 4G networks and 5G networks, allof which are hereinafter referred to as LTE networks. Some embodimentsparticularly relate to narrowband NB-IoT systems.

The following description and the drawings sufficiently illustratespecific embodiments to enable those skilled in the art to practicethem. Other embodiments may incorporate structural, logical, electrical,process, and other changes. Portions and features of some embodimentsmay be included in, or substituted for, those of other embodiments.Embodiments set forth in the claims encompass all available equivalentsof those claims.

FIG. 1 shows an example of a portion of an end-to-end networkarchitecture of a network (e.g., an LTE network) with various componentsof the network, in accordance with some embodiments. In particular, somecommunications between evolved universal mobile telecommunicationssystem terrestrial radio access nodes (evolved node Bs or eNBs) 104 andUEs 102 may involve MTC that have different resource demands than userapplication driven communications. In various embodiments, these MTCoperations may be used in an LTE network such as the networks of FIGS.1-3, or in any other such communication network. As used herein, an LTEnetwork refers to both LTE and LTE-A networks as well as other versionsof LTE networks in development, such as 4G and 5G LTE networks. Thenetwork may comprise a radio access network (RAN) (e.g., as depicted,the Evolved Universal Mobile Telecommunications System (UMTS)Terrestrial Radio Access Network (E-UTRAN) or evolved universalterrestrial radio access network) 100 and a core network 120 (e.g.,shown as an evolved packet core (EPC)) coupled together through an S1interface 115. For convenience and brevity, only a portion of the corenetwork 120, as well as the RAN 100, is shown in the example.

The core network 120 may include a mobility management entity (MME) 122,a serving gateway (serving GW) 124, and a packet data network gateway(PDN GW) 126. The RAN 101 may include evolved node Bs (eNBs) 104 (whichmay operate as base stations) for communicating with UE 102. The eNBs104 may include macro eNBs 104 and low power (LP) eNBs 104. The eNBs 104and UEs 102 may employ the techniques described herein.

The MME 122 may be similar in function to the control plane of legacyServing General Packet Radio Service (GPRS) Support Nodes (SGSN). TheMME 122 may manage mobility aspects in access such as gateway selectionand tracking area list management. The serving GW 124 may terminate theinterface toward the RAN 101, and route data packets between the RAN 101and the core network 120. In addition, the serving GW 124 may be a localmobility anchor point for inter-eNB handovers and also may provide ananchor for inter-3GPP mobility. Other responsibilities may includelawful intercept, charging, and some policy enforcement. The serving GW124 and the MME 122 may be implemented in one physical node or separatephysical nodes.

The PDN GW 126 may terminate a SGi interface toward the packet datanetwork (PDN). The PDN GW 126 may route data packets between the corenetwork 120 and the external PDN, and may perform policy enforcement andcharging data collection. The PDN GW 126 may also provide an anchorpoint for mobility devices with non-LTE access. The external PDN can beany kind of Internet Protocol (IP) network, as well as an IP MultimediaSubsystem (IMS) domain. The PDN GW 126 and the serving GW 124 may beimplemented in a single physical node or separate physical nodes.

The eNBs 104 (macro and micro) may terminate the air interface protocoland may be the first point of contact for a UE 102. In some embodiments,an eNB 104 may fulfill various logical functions for the RAN 101including, but not limited to, RNC (radio network controller) functionssuch as radio bearer management, uplink and downlink dynamic radioresource management and data packet scheduling, and mobility management.In accordance with embodiments, the UEs 102 may be configured tocommunicate orthogonal frequency division multiplexed (OFDM)communication signals with an eNB 104 over a multicarrier communicationchannel in accordance with an orthogonal frequency-division multipleaccess (OFDMA) communication technique. The OFDM signals may comprise aplurality of orthogonal subcarriers.

The S1 interface 115 may be the interface that separates the RAN 101 andthe core network 120. It may be split into two parts: the S1-U, whichmay carry traffic data between the eNBs 104 and the serving GW 124, andthe S1-MME, which may be a signaling interface between the eNBs 104 andthe MME 122. The X2 interface may be the interface between eNBs 104. TheX2 interface may comprise two parts, the X2-C and X2-U. The X2-C may bethe control plane interface between the eNBs 104, while the X2-U may bethe user plane interface between the eNBs 104.

With cellular networks, LP eNBs 104 b may be typically used to extendcoverage to indoor areas where outdoor signals do not reach well, or toadd network capacity in areas with dense usage. In particular, it may bedesirable to enhance the coverage of a wireless communication systemusing cells of different sizes, macrocells, microcells, picocells, andfemtocells, to boost system performance. The cells of different sizesmay operate on the same frequency band, or may operate on differentfrequency bands, with each cell operating in a different frequency bandor only cells of different sizes operating on different frequency bands.As used herein, the term LP eNB refers to any suitable relatively LP eNBfor implementing a smaller cell (smaller than a macro cell) such as afemtocell, a picocell, or a microcell. Femtocell eNBs may be typicallyprovided by a mobile network operator to its residential or enterprisecustomers. A femtocell may be typically the size of a residentialgateway or smaller and generally connect to a broadband line. Thefemtocell may connect to the mobile operator's mobile network andprovide extra coverage in a range of typically 30 to 50 meters. Thus, aLP eNB 104 b might be a femtocell eNB since it is coupled through thePDN GW 126. Similarly, a picocell may be a wireless communication systemtypically covering a small area, such as in-building (offices, shoppingmalls, train stations, etc.) or, more recently, in-aircraft. A picocelleNB may generally connect through the X2 link to another eNB such as amacro eNB through its base station controller (BSC) functionality. Thus,a LP eNB 104 b may be implemented with a picocell eNB since it may becoupled to a macro eNB 104 a via an X2 interface. Picocell eNBs or otherLP eNBs 104 b may incorporate some or all functionality of a macro eNB104 a or LP eNB 104 a. In some cases, this may be referred to as anaccess point base station or enterprise femtocell.

Communication over an LTE network may be split up into 10 ms radioframes, each of which may contain ten 1 ms subframes. Each subframe ofthe frame, in turn, may contain two slots of 0.5 ms. Each subframe maybe used for uplink (UL) communications from the UE 102 to the eNB 104 ordownlink (DL) communications from the eNB 104 to the UE 102. In oneembodiment, the eNB 104 may allocate a greater number of DLcommunications than UL communications in a particular frame. The eNB 104may schedule transmissions over a variety of frequency bands. Each slotof the subframe may contain 6-7 OFDM symbols, depending on the systemused. In one embodiment, each subframe may contain 12 subcarriers. Inthe 5G system, however, the frame size (ms), the subframe size, and thenumber of subframes within a frame, as well as the frame structure, maybe different from those of a 4G or LTE system. The subframe size, aswell as the number of subframes in a frame, may also vary in the 5Gsystem from frame to frame. For example, while the frame size may remainat 10 ms in the 5G system for downward compatibility, the subframe sizemay be decreased to 0.2 ms or 0.25 ms to increase the number ofsubframes in each frame.

A downlink resource grid may be used for downlink transmissions from aneNB to a UE, while an uplink resource grid may be used for uplinktransmissions from a UE to an eNB or from a UE to another UE. Theresource grid may be a time-frequency grid, which is the physicalresource in the downlink in each slot. The smallest time-frequency unitin a resource grid may be denoted as a resource element (RE). Eachcolumn and each row of the resource grid may correspond to one OFDMsymbol and one OFDM subcarrier, respectively. The resource grid maycontain resource blocks (RBs) that describe the mapping of physicalchannels to resource elements and physical RBs (PRBs). A PRB may be thesmallest unit of resources that can be allocated to a UE. A RB in someembodiments may be 180 kHz wide in frequency and 1 slot long in time. Infrequency, RBs may be either 12×15 kHz subcarriers or 24×7.5 kHzsubcarriers wide, dependent on the system bandwidth. In FrequencyDivision Duplexing (FDD) systems, both the uplink and downlink framesmay be 10 ms and frequency (full-duplex) or time (half-duplex)separated. The duration of the resource grid in the time domaincorresponds to one subframe or two resource blocks. Each resource gridmay comprise 12 (subcarriers)*14 (symbols)=168 resource elements.

Each OFDM symbol may contain a cyclic prefix (CP), which may be used toeffectively eliminate Inter Symbol Interference (ISI), and a FastFourier Transform (FFT) period. The duration of the CP may be determinedby the highest anticipated degree of delay spread. Although distortionfrom the preceding OFDM symbol may exist within the CP, preceding OFDMsymbols do not enter the FFT period with a CP of sufficient duration.Once the FFT period signal is received and digitized, the receiver mayignore the signal in the CP.

FIG. 2 illustrates a wireless network 200, in accordance with someembodiments. The wireless network 200 includes a UE 201 and an eNB 250connected via one or more channels 280, 285 across an air interface 290.The UE 201 and eNB 250 communicate using a system that supports controlsfor managing the access of the UE 201 to a network via the eNB 250.

In the wireless network 200, the UE 201 and any other UE in the systemmay be, for example, laptop computers, smartphones, tablet computers,printers, machine-type devices such as smart meters or specializeddevices for healthcare monitoring, remote security surveillance systems,intelligent transportation systems, or any other wireless devices withor without a user interface. The eNB 250 provides the UE 201 networkconnectivity to a broader network (not shown). This LE 201 connectivityis provided via the air interface 290 in an eNB service area provided bythe eNB 250. In some embodiments, such a broader network may be a widearea network (WAN) operated by a cellular network provider, or may bethe Internet. Each eNB service area associated with the eNB 250 issupported by antennas integrated with the eNB 250. The service areas aredivided into a number of sectors associated with certain antennas.

The UE 201 includes control circuitry 205 coupled with transmitcircuitry 210 and receive circuitry 215. The transmit circuitry 210 andreceive circuitry 215 may each be coupled with one or more antennas. Thecontrol circuitry 205 may be adapted to perform operations associatedwith wireless communications using congestion control. The controlcircuitry 205 may include various combinations of application specificcircuitry and baseband circuitry. The transmit circuitry 210 and receivecircuitry 215 may be adapted to transmit and receive data, respectively,and may include radio frequency (RF) circuitry or front end module (FEM)circuitry. In various embodiments, aspects of the transmit circuitry210, receive circuitry 215, and control circuitry 205 may be integratedin various ways to implement the circuitry described herein. The controlcircuitry 205 may be adapted or configured to perform various operationssuch as those described elsewhere in this disclosure related to a UE.The transmit circuitry 210 may transmit a plurality of multiplexeduplink physical channels. The plurality of uplink physical channels maybe multiplexed according to time division multiplexing (TDM) orfrequency division multiplexing (FDM) along with carrier aggregation.The transmit circuitry 210 may be configured to receive block data fromthe control circuitry 205 for transmission across the air interface 290.Similarly, the receive circuitry 215 may receive a plurality ofmultiplexed downlink physical channels from the air interface 290 andrelay the physical channels to the control circuitry 205. The pluralityof downlink physical channels may be multiplexed according to TDM or FDMalong with carrier aggregation. The transmit circuitry 210 and thereceive circuitry 215 may transmit and receive both control data andcontent data (e.g., messages, images, video, etc.) structured withindata blocks that are carried by the physical channels.

FIG. 2 also illustrates the eNB 250, in accordance with variousembodiments. The eNB 250 circuitry may include control circuitry 255coupled with transmit circuitry 260 and receive circuitry 265. Thetransmit circuitry 260 and receive circuitry 265 may each be coupledwith one or more antennas that may be used to enable communications viathe air interface 290.

The control circuitry 255 may be adapted to perform operations formanaging channels and congestion control communications used withvarious UEs, including communication of open mobile alliance managementobjects (OMA-MOs) describing application categories as detailed furtherbelow. The transmit circuitry 260 and receive circuitry 265 may beadapted to transmit and receive data, respectively, to any UE connectedto the eNB 250. The transmit circuitry 260 may transmit downlinkphysical channels comprised of a plurality of downlink subframes. Thereceive circuitry 265 may receive a plurality of uplink physicalchannels from various UEs including the UE 201.

In some releases of 3GPP LTE standards, a Physical Downlink ControlChannel (PDCCH) was defined, which spans the entire system bandwidth and{1,2,3} Orthogonal Frequency-Division Multiplexing (OFDM) symbols forsystem bandwidths larger than 1.4 MHz and {2,3,4} OFDM symbolsotherwise. The span of the PDCCH in the time domain-in number of OFDMsymbols—is dynamically signaled on the first OFDM symbol of everysubframe by means of a Control Format Indicator (CFI) transmitted on thePhysical Control Format Indicator Channel (PCFICH). After successfullydecoding the PCFICH on the first OFDM symbol, the UE can determine thePDCCH resources and commence decoding the PDCCH.

The eNB scheduler of the 3GPP LTE Rel. 8-14 wireless communicationssystem can dynamically adapt the code rate of the PDCCH to use the PDCCHresources. To this end, different Aggregation Levels (ALs) are defined,with each of them representing a different code rate for thetransmission of Downlink Control Information (DCI). The UE, since itdoes not a priori know the dynamically adapted code rate of thetransmitted DCI, blindly detects the aggregation levels (AL) of a PDCCH.For decoding of the PDCCH while maintaining utmost flexibility at theeNB encoder, search spaces are defined that map the physical resourcesin the PDCCH region to a logical numbering of Control Channel Elements(CCEs). The aforementioned ALs are defined based on these CCEs. Forexample, aggregation levels {1,2,4,8} correspond to {1,2,4,8} CCEs wherethe exact CCE indices for the {1,2,4,8} CCEs depend on the Search Space(SS) definition. This detection of aspects of the PDCCH is referred toherein as blind detection or blind decoding. In various embodiments,blind decoding refers to a device (e.g. a UE) having limited orincomplete information to decode a channel, and attempting multiplecombinations of decoding options (e.g. blind decoding trials) todetermine the correct combination for decoding.

In 3GPP LTE Release 11, a new control channel was introduced called theenhanced PDCCH (EPDCCH). The EPDCCH is transmitted on a subset of thePhysical Resource Blocks (PRBs) and spans the entire subframe, in thetime domain, in those PRB-pairs configured for EPDCCH transmission bythe Radio Resource Control (RRC) protocol. For example, {2,4,8} PRBpairs may be reserved for EPDCCH transmissions within which the UE willattempt to blindly decode the EPDCCH. The mapping of the physicalresources in the configured PRB pairs for EPDCCH transmission followsthe same principle as does the PDCCH, i.e., enhanced CCE (ECCEs) aredefined that map the Resource Elements (REs) in the configured EPDCCHresources to logical ECCE indices on which the search space is defined.The eNB scheduler can again dynamically adapt the code rate of the DCItransmission on the EPDCCH by changing the aggregation level of theEPDCCH, where the AL is similarly defined by different numbers of ECCEsto which the EPDCCH is mapped, i.e., the number of modulated symbols canvary depending on the number of allocated ECCEs. The EPDCCH supports ALs{1,2,4,8,16,32}.

The mapping of the logical search space to the physical resources usedfor transmission of the DCI differs for both the EPDCCH and PDCCH. Forthe latter, CCEs are mapped to resource elements (physical resources fortransmission of the PDCCH) by definition of Resource Element Groups(REGs), and one control channel element corresponds to nine resourceelement groups. The number of REGs (and consequently the number of CCEs)in one subframe is a cell-specific function of the dynamically signaledCFI and the broadcasted system information of the cell. For example,after decoding the Physical Broadcast Channel (PBCH), the LIE obtainsthe Physical HARQ Indicator Channel (PHICH) configuration of the cellwhich is carried in the Master Information Block (MIB) transmitted onthe PBCH. Said PHICH configuration, together with the cell-specificantenna port (AP) configuration of the cell and the CFI, determines thetotal number of REGs NREG in the given subframe, which the UE candeterministically obtain from decoding the PBCH and PCFICH. Based on theknowledge of NREG, the UE receiver can determine the search space andproceed to decode the PDCCH candidates in the subframe.

For the EPDCCH, on the other hand, the number of EREGs per subframe isfixed by specification. There are 16 EREGs, numbered from 0 to 15, perphysical resource block pair. As a consequence, the actual number of REsin an EREG used for transmission of EPDCCH may differ, whereas for thePDCCH, one REG always comprises four resource elements (termed aquadruplet of symbols). For example, the actual number of EPDCCH REswithin an EREG may depend on the cell's Cell-specific Reference Signal(CRS) configuration, a UE's Channel State Information Reference Signal(CSI-RS) configuration, and so forth.

In 3GPP LTE Rel. 13, yet another two control channels were defined: theM-PDCCH and the NB-PDCCH. The former is defined for a legacy LTE systembandwidth, namely, six PRBs. The latter, however, is restricted to a 180kHz RF bandwidth corresponding to a single PRB with 15 kHz sub-carrierspacing of the Orthogonal Frequency-Division Multiplexing (OFDM)waveform. The narrowband nature of the NB-PDCCH (for narrowband PDCCH)makes the control channel design particularly challenging. Embodimentsherein relate to novel control channel formats and associated NB-REG andNB-CCE definitions for efficient operation of the control channel in anarrowband (NB) OFDM system.

In some embodiments, for efficient operation of a narrowband LTE(NB-LTE) or narrowband Internet-of-Things (NB-IoT) wirelesscommunications system, control channel resources need to be adjustableto the coverage condition of narrowband UE in a dynamic fashion. Severalconsiderations make the control channel design particularly challenging,including the narrowband nature of the NB-IoT system (e.g., a singlePhysical Resource Block (PRB) may be available per Transmission TimeInterval (TTI), which renders the available resources for transmissionof Downlink Control Information (DCI) particularly scarce). Moreover,additional robustness is used in the design of IoT systems owing to thechallenging coverage conditions in which IoT devices may be deployed(e.g., water meters, gas meters, electricity meters, devices inunderground locations, etc.) Further, simplicity of the design iscrucial to facilitate low cost and low complexity implementations of theIoT receiver circuitry, a fundamental requirement stemming from thelarge number of IoT devices to be deployed in smart cities.

Trading off the aforementioned performance indicators such asefficiency, simplicity, and robustness leads to new design paradigmsthat may vastly differ from traditional control channel designs formobile broadband UE. In particular, the mapping of logical ControlChannel Elements (CCEs) on which the search spaces are defined thatallow the IoT UE to decode the NB-PDCCH to physical resources fortransmission of the NB-PDCCH waveform take these constraints intoaccount. The disclosure herein relates to narrowband search spacedesign, narrowband resource mapping definitions and procedures,multiplexing of narrowband control channel transmissions, scheduling ofNB-IoT UEs in different coverage conditions, and so forth.

The Third Generation Partnership Project (3GPP) introduced a narrowbandInternet-of-Things (NB-IoT) design into its Release 13 specifications ofthe Long-Term Evolution (LTE) wireless mobile communications standard.The 3GPP LTE NB-IoT specifications define a Radio Access Technology(RAT) for a cellular Internet-of-Things (CIoT) based on anon-backward-compatible variant of the evolved Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (E-UTRA)standard specifically tailored towards improved indoor coverage, supportfor a massive number of low throughput devices, low delay sensitivity,ultra-low device cost, low device power consumption, and (optimized)network architecture.

The 3GPP LTE NB-IoT standard furthermore supports three different modesof operation: stand-alone, guard-band, and in-band. For the former two,all resources within the NB-IoT carrier are available for transmissionof NB-IoT signals and channels. A NB-IoT carrier generally comprises onelegacy LTE Physical Resource Block (PRB) corresponding to a systembandwidth of 180 kHz for a subcarrier spacing of 15 kHz. LTE NB-IoT (orNB-LTE) is based on Orthogonal Frequency-Division Multiple Access(OFDMA) in the downlink (DL) and Single-Carrier Frequency-DivisionMultiple Access (SC-FDMA) in the uplink (UL). Different numerologies maybe supported and the embodiments herein shall apply to any suchnumerology.

In accordance with embodiments described herein, an NB-IoT physicallayer design uses a subset of the channels defined for legacy LTEsystems. Thus, some channels may not be defined for NB-IoT systems. AnNB-IoT UE may perform a cell search to identify a suitable cell toconnect to the Internet. The NB-IoT UE attempts to detect a narrowbandPrimary Synchronization Signal (NB-PSS). The NB-IoT UE may also use theNB-PSS to synchronize its clock with the NB-IoT network and to detectthe symbol boundaries of the OFDM waveforms. The NB-IoT UE then attemptsto obtain the downlink subframe and frame timing as well as the PhysicalCell ID (PCI) of the NB-IoT carrier using a narrowband SecondarySynchronization Signal (NB-SSS). From the cell ID and the radio framesynchronization, the UE can proceed to decode the narrowband PhysicalBroadcast Channel (NB-PBCH), which may contain scheduling informationfor additional system information transmissions. Acquiring the NB-IoTsystem information will enable the NB-IoT UE to initiate a Random Access(RA) procedure to attach to the NB-IoT network. The network responds tothe random access procedure with a Random Access Response (RAR). Therandom access procedure allows the network to configure the NB-IoT UEfor communication with the network and may comprise a contentionresolution procedure. After connection establishment, the network canconfigure the NB-IoT UE with cell-specific and UE-specific RadioResource Control (RRC) parameters to control the NB-IoT UE'stransmission and reception behavior.

Most communication between the NB-IoT UE and the network are scheduledby the NB-PDCCH. An exception is the use of the Random Access Channel(RACH)). The NB-PDCCH conveys Downlink Control Information (DCI) fromthe eNB to the NB-IoT UE that schedules NB-PDSCH and NB-PUSCHtransmissions in the downlink and uplink, respectively. Other channelsmay not be needed in an NB-LTE system but are not precluded.

Demodulation of the NB-PBCH, NB-PDCCH, and NB-PDSCH may be based onCell-specific Reference Signals (CRS), Demodulation Reference Signals(DMRS), or Narrowband Reference Signals (NB-RS), although these are notmeant to be construed in a limiting sense and other naming conventionsare not precluded. Moreover, different channels may be modulated usingdifferent reference signals. Lastly, a single channel may be demodulatedusing several reference signals. For example, the NB-PBCH may bedemodulated using NB-RS, whereas the NB-PDCCH may be demodulated usingCRS. In a different example, the NB-PDCCH may be demodulated using CRSwhen the NB-IoT UE is in good coverage conditions whereas other NB-IoTUEs may use both CRS and NB-RS to demodulate the NB-PDCCH. Even moreexamples will be apparent to a person of skill in the art.

For various embodiments, the NB-PDCCH, irrespective of its detailedphysical layer (PHY) design, allows an NB-IoT UE to decode the NB-PDCCHwithout prior knowledge of the physical resources used for transmissionof the NB-PDCCH. Unlike the narrowband Physical Downlink Shared Channel(NB-PDSCH) and the narrowband Physical Uplink Shared Channel (NB-PUSCH),whose transmissions are scheduled by DCI comprising the resourceallocation and Adaptive Modulation and Coding (AMC) scheme of thetransmission, NB-IoT UEs decode the NB-PDCCH without such a prioriknowledge. Assuming a fixed modulation scheme for the NB-PDCCH (e.g.,Quadrature Phase Shift Keying (QPSK)) and deterministic payload sizes ofthe DCI, the eNB scheduler can adapt the code rate of a NB-PDCCHtransmission by dynamically changing the number of Resource Elements(REs) in the time-frequency grid allocated to a given NB-PDCCH. TheNB-IoT UE, in attempting to decode the NB-PDCCH, will blindly decode adefined set of physical resources called a Search Space (SS) forpossible NB-PDCCH transmissions whereby a NB-PDCCH is successfullydecoded when the Cyclic Redundancy Check (CRC) passes for a NB-PDCCHcandidate. Search spaces are logical concepts that are mapped tophysical resources by means of Control Channel Elements (CCEs). Inembodiments described herein, NB-CCEs shall denote CCEs used to definethe mapping to physical resource elements for the NB-PDCCH, however,such a naming convention is not meant to be construed in a limitingsense and other terminologies are not precluded. In particular, a NB-IoTUE will attempt to decode a NB-PDCCH for different code rate hypothesescalled Aggregation Levels (ALs), whereby each AL maps to differentnumber of NB-CCEs assumed for transmission of the NB-PDCCH. In otherwords. NB-PDCCH candidates are defined as a function of both the AL andthe CCE indices of a given NB-PDCCH candidate

In some embodiments described herein, the number of candidates for agiven AL is a priori known to the UE as is the search space definition.Furthermore, the search space definition may comprise a hashing functionto randomize CCE indices across subframes to prevent blocking amongdifferent NB-IoT UEs. Lastly, logical CCEs are mapped to physicalresources used for transmission of the NB-PDCCH by means of ResourceElement Groups (REGs). In embodiments described herein. NB-REGs shalldenote REGs used to define the mapping of NB-CCEs to physical resourceelements; however, such a naming convention is not meant to be construedin a limiting sense and other terminologies are not precluded.

In one embodiment, one NB-CCE corresponds to one PRB-pair. MultipleNB-PDCCHs are multiplexed in a time-division multiplexing (TDM) manner.For example, one NB-PDCCH may be transmitted to one NB-IoT UE insubframe n whereas another NB-PDCCH may be transmitted to another NB-IoTUE in subframe n+1. In a different example, a first NB-IoT UE is in goodcoverage and is allocated AL=2, whereas a second NB-IoT UE is in extremecoverage and is allocated AL=8. Good [extreme] coverage in this examplemeans that the Mutual Coupling Loss (MCL) between the eNB transmitterand the NB-IoT UE receiver is small (large). The NB-PDCCH for a firstNB-IoT UE may then be transmitted in subframes n and n+1, whereas theNB-PDCCH for a second NB-IoT UE is transmitted in subframes n+2, n+3,n+4, . . . n+9. This search space definition may be denoted “localized”as the NB-CCEs comprising one NB-PDCCH are in consecutive subframes.

In some embodiments, as described with respect to some embodiments, ALsmay be defined only within a subframe and the accumulation of NB-CCEsacross multiple subframes may also be referred to using RepetitionLevels (RLs). Hence, for the above embodiment wherein one NB-CCEcorresponds to one PRB-pair, this could imply AL=1 is always used anddifferent search space candidates are defined by different RLs (e.g. UEsmonitor for different sets of RLs.) Thus, for the above example, AL=1for both UEs, and RL=2 and RL=8 for the first and second UEs,respectively.

In another embodiment, a first NB-IoT UE is again in good coverage andis allocated AL=2, whereas a second NB-IoT UE is again in extremecoverage and is allocated AL=8. However, in this example, subframes nand ¬n+k are allocated to a first NB-IoT UE whereas subframes {n+1,¬n+k+1, ¬n+2×k+1, ¬+3×k+1, . . . ¬n+7×k+1} are allocated to a secondNB-IoT UE. Note that such a division of subframes is merely chosen forease of exposition and is not meant to be construed in a limiting sense.Other more complicated multiplexing schemes can be envisioned and thedifferentiating characteristic of this embodiment is that a singleNB-PDCCH is not mapped to NB-CCEs in consecutive subframes. Such asearch space definition may be denoted “distributed.” One motivation forsuch a distributed search space definition is to prevent blocking amongmultiple NB-IoT UEs. In some embodiments, for the localized search spacedefinition, a second NB-IoT UE cannot be scheduled while the NB-PDCCHtransmission to a first NB-IoT UE is on-going. For the distributed kind,NB-PDCCH transmissions for several NB-IoT UEs can be multiplexed in thetime domain. In a different example, this distributed approach can helpaddress user blocking mainly when a UE with good channel conditions(e.g., the first UE) is “squeezed” within a large number of repetitionsbeing transmitted to another UE (e.g., the second UE). It may be morebeneficial to distribute the subframes for a UE in poor channelconditions that use more repetitions or higher aggregation levels (e.g.,if aggregation levels are defined across subframes) so that other UEs,potentially with good channel conditions, can be addressed within thesame set of transmissions as the UE with worse channel conditions. Inone embodiment, distributed mapping of the NB-PDCCH in time-domain isused for UEs with a Maximum Coupling Loss (MCL) above a certainthreshold or when the search space of NB-PDCCH candidates includesrepetition (or aggregation) levels higher than a certain otherthreshold. These thresholds can be specified (e.g., MCL>154 dB orrepetition level>16).

In yet another embodiment, NB-CCEs comprise the entire PRB similar tothe aforementioned two embodiments. In some embodiments, in addition,they are further sub-divided into NB-REGs. In one example, one NB-REGcomprises the resource elements on a single subcarrier in a givensubframe. For example, assuming k=1 . . . , Nsc subcarriers per PRB.NB-REG k corresponds to resource elements (k,l) where k is thesubcarrier index and l is the OFDM symbol within a subframe, l=0, 1,2, .. . , Nsymb−1, where Nsymb is the number of OFDM symbols within asubframe. In another example, the NB-REG numbering is slightly alteredand NB-REG k′ corresponds to subcarrier index k for even k and NB-REG k′corresponds to subcarrier index Nsc-k for odd k, k=1, 2, . . . , Nsc.This is also exemplified in Table 1 for Nsc=12.

TABLE 1 An example for NB-REG indexing and mapping to subcarriers k′ k 0  0  1 11  2  2  3  9  4  4  5  7  6  6  7  5  8  8  9  3 10 10 11  1

Such an NB-REG definition may be beneficial if modulated NB-PDCCHsymbols are mapped to the dc subcarrier of the OFDM waveform. A “timefirst” mapping can also be combined with Space Frequency Block Codes(SFBC) to harness additional transmit diversity. In one embodiment, thetime-first mapping is performed in pairs of sub-carriers and SFBC isapplied to these pairs. Within a pair, the symbols are first mapped inthe frequency domain and then in the time domain (e.g., SFBC isperformed on symbols of sub-carriers k=2*i+o for o={0,1} andi={0,1,2,3,4,5}). Alternatively, Table 1 can be adopted to support SFBCas exemplified in Table 2.

TABLE 2 An example for NB-REG indexing and mapping to subcarriers k′ k 0  0  1  1  2 10  3 11  4  2  5  3  6  8  7  9  8  4  9  5 10  6 11  7

In some embodiments, in the above NB-REG definition, the number ofNB-REGs is constant. In some such embodiments, the number of NB-REGsequals Nsc. When the NB-IoT carrier is deployed within the systembandwidth of a legacy LTE network, cell-specific signals and channels ofthe legacy LTE network are structured to be protected by the NB-IoTsystem. For example, NB-IoT signals and channels may not be mapped tothe first one, two, or three OFDM symbols of a subframe where the legacyLTE system may transmit the legacy PDCCH. Similarly, resource elementsused for transmission of CRS in the donor PRB (e.g., the PRB used forNB-IoT transmissions within the LTE system bandwidth) may be protectedand cannot be used for transmission of NB-IoT signals and channels.NB-IoT UEs may be aware of such protected resources either byspecification (e.g., for the legacy control region) or via signalingfrom the eNB providing the NB-IoT carrier. For example, the NB-IoT UEmay infer the legacy CRS resources from detecting the Physical Cell IDfrom the NB-SSS transmission. Alternatively, the NB-PBCH may carry suchinformation. In some embodiments, the NB-PBCH or the MIB transmitted onthe NB-PBCH may also contain the PRB index of the NB-IoT carrier and thenumber of PBCH antenna ports of the legacy donor PRB. Alternatively, thenumber of PBCH antenna ports of the legacy donor PRB may be encoded inthe CRC bits of the NB-PBCH by means of a scrambling mask. Once theNB-IoT UE has deterministically derived the protected resources, it canrate match the NB-PDCCH around these resources accordingly. For example,the NB-IoT UE may assume that resource elements defined by the NB-REGsof a NB-PDCCH candidate that collide with protected resources may not beused for NB-PDCCH transmissions. Assuming a NB-REG definition as inTable 1, NB-PDCCH symbols may be mapped to OFDM symbols starting afterthe OFDM symbols corresponding to legacy PDCCH transmissions for NB-IoTdeployments in an in-band mode of operation. Similarly. REs used forlegacy CRS and NB-RS and/or DMRS transmissions may be excluded from aNB-REG when the NB-PDCCH is mapped to physical resources.

In another embodiment, the number of REs within a NB-REG used fortransmission of the NB-PDCCH is constant. For example, ine oneembodiment one NB-REG may always comprise four REs to which the NB-PDCCHis mapped. In this example, the number of NB-REGs within a subframe willbe different depending on the NB-IoT mode of operation (for in-banddeployments, NB-REGs are not defined for the first one, two, or threeOFDM symbols of a subframe corresponding to the LTE PDCCH region), thenumber of PBCH antenna ports in the legacy LTE donor cell (8, 16, or 24REs are reserved for LTE CRS for 1, 2, 4 PBCH antenna ports,respectively) and the number of REs reserved for mapping of RS used todemodulate the NB-PDCCH.

In yet another embodiment, multiple NB-PDCCH may be multiplexed withinone subframe. Such a multiplexing of NB-PDCCHs is based on the NB-REGand/or NB-CCE definitions, according to some embodiments herein. Forexample, one NB-CCE may be defined as four NB-REGs according to Table 1.Assuming 12 subcarriers per PRB, three NB-PDCCH can be multiplexedwithin the same subframe where one NB-CCE comprises four NB-REGs. Such aNB-REG to NB-CCE mapping is not meant to be construed in a limitingsense and other mappings are not precluded.

In various embodiments, the aforementioned NB-REG definitions can becombined. For example, the number of NB-REGs per subframe can by dynamic(e.g., as a function of the deployment mode and/or the number ofreference signals used for demodulation of the NB-PDCCH), yet theNB-REGs may be punctured by other RS of which the NB-IoT UE may not beaware. For example, CSI-RS may puncture the NB-REGs from an eNBperspective, but the NB-IoT UE may not be aware of the respective CSI-RSconfiguration and thus does not take CSI-RS definitions into accountwhen determining the number of NB-REGs within a subframe.

In yet another embodiment, the NB-REG and/or NB-CCE definition maydepend on the mode of operation, which may be signaled by the NB-PSS,NB-SSS, or NB-PBCH.

In yet another embodiment, the search space definitions depend on theactual or assumed (from the NB-IoT UE perspective) number of availableREs for NB-PDCCH transmission within one subframe. For example, if thenumber of actual or assumed REs for NB-PDCCH transmissions is less thana threshold T, then the minimum aggregation level is larger than for thecase where the number of actual or assumed REs for NB-PDCCHtransmissions is larger than a threshold T. In addition oralternatively, the threshold may depend on the DCI payload size for agiven NB-PDCCH candidate. For example, for the in-band mode ofoperation, the minimum number of NB-CCEs per NB-PDCCH may be larger thanfor the guard-band or standalone mode of operation due to the loss ofNB-PDCCH resources stemming from the protection of legacy channels andsignals in the donor PRB.

In some embodiments, it is assumed that the NB-PDCCH search spacecandidates are defined using a pair of aggregation levels (ALs) andrepetition levels (RLs) to monitor, wherein an AL is defined as thenumber of NB-CCEs used within a subframe to transmit an NB-PDCCH and anRL is defined as the number of subframes over which the NB-CCE(s) arerepeated in a time dimension. Further, across the different repetitionsin different subframes, the same NB-CCE location(s) can be used totransmit the NB-PDCCH (e.g., the NB-CCE(s) are the same as those used inthe first subframe for the particular NB-PDCCH candidate).Alternatively, a permutation of the NB-CCE index could be applied as afunction of the System Frame Number (SFN) and subframe index, whereinthe permutation function is based on a hashing function. However,different definitions for ALs and/or RLs may be realized and,accordingly, the concepts disclosed next can be adapted.

In another embodiment, each NB-REG is formed by a maximum of four REsor, alternatively, formed by a maximum of six REs, with the actualnumber of REs used to carry NB-PDCCH in the NB-REG depending on thepresence of LTE CRS and NB-RS within the NB-REG REs in the PRB-pair ofthe NB-IoT subframe. Thus, an NB-REG is represented by the index pair(k′, l′) of the resource element with the lowest index k in the groupwith all resource elements in the group having the same value of 1. Theset of resource elements (k,l) in a resource-element group depends onthe number of LTE cell-specific reference signals (LTE CRS) andNarrowband reference signals (NB-RS) configured. The indexing for k in(k,l) can be limited to range from 0 through 11, corresponding to thetwelve subcarriers in a PRB of the NB-IoT subframe. Alternatively,indexing for k in (k,l) can be defined as the subcarrier indexing usingfor LTE PDCCH such the index of the NB-IoT PRB within the larger LTEsystem BW (for in-band operation mode), and a specified or configured(e.g., signaled via the NB-PDCCH) value, e.g., nPRB=0 (for stand-aloneor guard-band operation modes). The REs in an NB-REG are mapped in afrequency-first mapping for NscNB-PDCCH subcarriers, where NscNB-PDCCHis the minimum number of subcarriers used for transmitting the NB-PDCCH.This value can depending on whether frequency-division multiplexing ofmultiple NB-PDCCH or NB-PDCCH and NB-PDSCH are supported within a PRB.For instance, NscNB-PDCCH=4 or NscNB-PDCCH=12 can be used when NB-REG isformed by a maximum of four REs, while NscNB-PDCCH=6 is used when NB-REGis formed by a maximum of six REs. That is, the NB-REG time index l′ isincremented by 1 every NscNB-PDCCH subcarriers.

In some of the embodiments, the OFDM symbols for NB-PDCCH mapping andhence, the mapping of time index l′ of the NB-REG, start after the LTEPDCCH symbols for in-band operation and can start from the first OFDMsymbol (symbol 0) for stand-alone and guard-band operation modes. Forin-band mode, the starting OFDM symbol for NB-PDCCH and NB-PDSCH can beconfigured semi-statically via the System Information Block (SIB)signaling defined for NB-IoT.

Using the above construction of NB-REG, a Narrowband Control ChannelElement (NB-CCE) can be defined to be comprised of the NB-REGs withinthe NscNB-PDCCH subcarriers and the available OFDM symbols (excludingthe LTE PDCCH symbols for in-band mode) of an NB-IoT subframe (assumedto be same as LTE subframe duration in this disclosure, but the conceptsherein can be adapted for longer subframe durations for NB-IoT). Thisapproach would be suitable especially when NscNB-PDCCH=4 orNscNB-PDCCH=6.

Alternatively, an NB-CCE can be defined to comprise a fixed number ofNB-REGs (e.g., 9 NB-REGs) and in this case, the number of used NB-REGsin a subframe is known to the UE. This approach may be suitable whenNscNB-PDCCH=12. For this case, if necessary, <NIL> elements are insertedin the block of bits prior to a scrambling operation to ensure that theNB-PDCCHs start at specific NB-CCE positions and that the length of thetotal number of bits transmitted for all the transmitted NB-PDCCH in thesubframe=Q*nRENB-REG*NNB-REG, where Q=2 corresponds to a modulationorder of QPSK, nRENB-REG indicates the maximum number of REs used toconstruct an NB-REG (e.g., 4 or 6 per the embodiments above), andNNB-REG is the number of NB-REGs used for NB-PDCCH transmission in asubframe. If NB-PDCCH and NB-PDSCH are not multiplexed in the same PRBpair of an NB-IoT subframe, then the value of NNB-REG can be determinedas nREsubframe/nRENB-REG, where nREsubframe is the number of availableREs (including those reserved for LTE CRS and NB-RS) excluding the LTEPDCCH symbols for in-band operation mode. When NscNB-PDCCH<12, then theabove concepts can be adapted as well.

Following the first embodiment for NB-CCE construction, in furtherembodiments, an NB-REG is composed of a maximum of 4 REs andNscNB-PDCCH=4, and thereby, NB-CCE is defined to span X NB-REGs, where Xis the number of OFDM symbols in the subframe used for NB-PDCCHtransmission. In this case, a single NB-PDCCH can be transmitted using 4subcarriers of a subframe when using a single NB-CCE, which is referredto as aggregation level (AL)=1 for NB-PDCCH transmission. Up to threeNB-CCEs and up to three NB-PDCCH can be transmitted in a singlesubframe, thereby reducing the impact of user blocking for DL or ULscheduling. However, for such embodiments, considering the presence ofLTE CRS with at least two DL antenna ports (APs) and/or NB-RS in thesubframe, for subcarriers 0 through 3, up to 22.22% fewer REs may beavailable for the NB-CCE compared to the NB-CCE mapped to subcarriers4-7 or subcarriers 8-11. This is due to the LTE CRS (similar RS patternis assumed for NB-RS w.r.t. frequency domain location) being mapped to 4subcarriers in a PRB for 2 or 4 APs.

In some further embodiments, to obtain evenly balanced available REs andeffective coding rates for different NB-CCEs in a subframe, an NB-REG iscomposed of a maximum of 6 REs, and NscNB-PDCCH=6, and NB-CCE is definedto span X NB-REGs, where X is the number of OFDM symbols in the subframeused for NB-PDCCH transmission. In this case, up to two NB-CCEs and upto two NB-PDCCH can be transmitted within a subframe, and the number ofREs in each NB-CCE would be the same, ranging from 50 REs (in-band with3 symbols for LTE PDCCH, 4-port LTE CRS, and 2-port NB-RS) to 76 REs(stand-alone or guard-band with NB-PDCCH starting from symbol 0, and2-port NB-RS). In some embodiments, for stand-alone or guard-band cases,the NB-RS can use similar structure and sequence design as LTE CRS witha specified PRB index.

In yet another embodiment, NB-REGs are not defined and instead NB-CCEsare directly defined such that the NB-PDCCH symbols are mapped in afrequency-first manner within the NscNB-PDCCH=4 or NscNB-PDCCH=6subcarriers and the available OFDM symbols in the subframe. In thiscase, the symbol to resource element mapping is performed by skipping(i.e., rate-matching around) the REs reserved for LTE CRS and/or NB-RS.

Further, for some implementations of the above embodiments, for theNB-PDCCH construction using NB-REG definitions, the mapping of theNB-PDCCH symbols to the NB-REGs can follow the procedure described inSection 6.8.5 of 3GPP TS 36.211.

Thus, the eNB can transmit up to 3 or 2 NB-PDCCH (for NscNB-PDCCH=4 or 6respectively) in a subframe. Additionally, a UE's search space can alsoinclude NB-PDCCH candidates using AL>1 (i.e., AL=2 or 3 wherein a singleNB-PDCCH is transmitted using 2 or 3 NB-CCEs within a PRB pair). Thus,depending on the traffic and loading on the NB-PDCCH, the eNB canconfigure a UE with larger AL and smaller repetition levels (RLs) orvice-versa. While use of larger ALs would benefit the UE in receivingthe NB-PDCCH quickly, thereby aiding power consumption reduction, thelatter, i.e., smaller ALs, can be used to multiplex multiple NB-PDCCH orNB-PDSCH in a PRB pair of an NB-IoT subframe.

For multiplexing with NB-PDSCH, similar to LTE EPDCCH operation, a UEmay not monitor for N B-PDCCH in the subcarrier set that has beenscheduled for NB-PDSCH transmission to the UE. Further, for the case ofNscNB-PDCCH=4 or 6. NB-PDCCH subcarrier sets or “NB-PDCCH sub-PRB sets”may be defined such that the UE would monitor a limited set of NB-PDCCHsubcarrier sets or NB-PDCCH sub-PRBs in a particular subframe. Thisinformation can be provided to the UE as part of the UE-specific searchspace (USS) or common search space (CSS) configurations carried viadedicated RRC signaling or SIB signaling (for CSS, if CSS is defined forNB-IoT).

Such a design can enable the eNB to multiplex different coverage classesvia FDM—e.g., using the NB-PDCCH sub-PRB sets of size 4 or 6 subcarriers(e.g., NscNB-PDCCH=4 or 6), the eNB can assign UEs in different coverageclasses to monitor different sets of the subcarriers within a PRB.

In some embodiments, NB-PDCCH is defined using a combination of theconcepts of NB-PDCCH sub-PRB sets, NB-REGs, and NB-CCEs as describedabove with the concepts described earlier including distributed mappingfor NB-CCE definition.

Some of the embodiments herein can also be employed to address theaforementioned blocking issue among different NB-IoT UEs. In oneembodiment, multiplexing of different NB-IoT UEs within a singlesubframe is used to address the blocking issue. In another embodiment,distributed NB-CCE definitions spanning more than one subframe can beused to multiplex multiple NB-PDCCHs in the time-domain according to theembodiments herein. In some embodiments, the blocking can be addressedby dynamically indicating the offset between the scheduling NB-PDCCH andthe associated NB-PDSCH in the DCI. For example, the DC may indicate anoffset parameter p in the DCI indicating an associated NB-PDSCH istransmitted in subframe n+p where subframe n is a reference subframeknown to the UE. Different trade-offs between scheduling flexibility andsimplicity of the design can be achieved as follows in variousembodiments. In some embodiments, a localized NB-CCE definition whereone NB-CCE corresponds to one PRB and the DCI indicates a dynamic offsetp is used. In some embodiments, a distributed NB-CCE definition whereone NB-CCE corresponds to one PRB and the offset p is fixed byspecification is used. In some embodiments, localized NB-CCE definitionwhere multiple NB-CCEs are defined in one PRB and the offset p is fixedby specification is used. In other embodiments, other such structuresare used.

For UE-specific search spaces, the multiplexing of NB-PDCCH fordifferent UEs with the same or different coverage classes can berealized in both frequency and time dimensions. This can be achieved viathe search space configuration that includes UE-specific sets of (AL,RL) that UEs monitor for NB-PDCCH. Further, the starting subframe of theNB-PDCCH search space can be defined UE-specifically as a function ofSFN, subframe number and considering the maximum repetition level (RL)used for any NB-PDCCH candidate for the UE's search space. Thus, thestarting subframe of the USS should be such that the periodicity is longenough to accommodate the maximum RL for the NB-PDCCH candidate(s) inthe search space.

In some embodiments, an NB-IoT UE can be configured to receive theNB-PDCCH on multiple NB-IoT carriers whereby each NB-IoT carrier has aRF bandwidth of 180 kHz corresponding to a single PRB assuming 15 kHzsub-carrier spacing of the Orthogonal Frequency-Division Multiplexing(OFDM) waveform; however, other numerologies are not precluded. In oneembodiment, the NB-IoT UE is configured with said NB-IoT carriers in aUE-specific manner by the controlling eNB. For example, an NB-IoT UE mayattach to an NB-IoT carrier by the aforementioned procedure comprisingdetection and subsequent decoding of the NB-PSS/SSS sequences and theNB-PBCH channel, respectively. After RRC connection establishment, theNB-IoT UE is configured with one or more NB-IoT carriers on which theNB-IoT begins to monitor for NB-PDCCH transmissions, according to someof the embodiments herein. Such a UE-specific RRC configuration may beperformed separately for the common search space (CSS) and theUE-specific search space (USS). Alternatively, the NB-IoT UE monitorsthe CSS on the NB-IoT carrier on which it received the NB-PBCH, whereasthe NB-IoT carrier(s) for transmission of NB-PDCCHs on the UE-specificsearch space are RRC configured. Similarly, the NB-IoT carrier(s) forreception of NB-PDSCHs may be RRC configured at the UE. In this example,the DCI would indicate on which NB-IoT carrier the NB-IoT UE decodes theassociated NB-PDSCH.

In another embodiment, the NB-IoT carrier with NB-PSS/SSS and/or NB-PBCHbroadcasts in the system information a set of candidate NB-IoT carriersfor this “anchor carrier.” The NB-IoT carriers for reception ofNB-PDCCHs on the USS and/or CSS may be informed to the NB-IoT UE viadedicated RRC signaling, whereas NB-PDSCH transmissions are dynamicallyscheduled on these candidate NB-IoT carriers through indication in theDCI.

In yet another embodiment, the NB-IoT UE monitors one or more NB-IoTcarriers for NB-PDCCH transmissions whereby which NB-IoT carrier tomonitor is determined by the NB-IoT UE's coverage class. In one example,NB-IoT UEs in good coverage condition monitor NB-PDCCH transmissionsaccording to the embodiments herein on one NB-IoT carrier, whereasNB-IoT UEs in extreme coverage condition monitor NB-PDCCH transmissionsaccording to the embodiments herein on another NB-IoT carrier.

In yet another embodiment, the NB-IoT carrier with NB-PSS/SSS and/orNB-PBCH broadcasts in the system information (e.g., NB-SIB1) on whichNB-IoT carrier the NB-IoT UE receives additional system information.

In some embodiments herein, the NB-IoT carriers may be configured by afrequency offset relative to the NB-IoT carrier with NB-PSS/SSS and/orNB-PBCH. Alternatively, the NB-IoT carriers may be configured using anindexing scheme. For example, when the multiple NB-IoT carriers aredeployed within a single LTE system bandwidth, the PRB indexing of theLTE donor system may be used to configure the NB-IoT carriers.

In accordance with the above, FIG. 3 illustrates a method 300 forcontrol channel communications in a NB-IoT system, in accordance withembodiments described herein. Method 300 describes operations 305, 308,310, and 315 performed at a UE such as UE 102 or 201, mobile device 600,or machine 800, using signals generated in operation 302 at an eNB suchas eNB 104 or 250. In various embodiments, the operations may beperformed by processing circuitry of the corresponding device. Someembodiments comprise instructions in a storage medium that, whenexecuted by processing circuitry, perform some or all of the describedoperations.

In some embodiments, operation 302 is a separate method performed by anapparatus of an evolved node B (eNB) for encoding control channelsignals for narrowband Internet-of-Things (IoT) communications, with theapparatus comprising a memory and processing circuitry in communicationwith the memory and arranged to encode a first control transmissionusing a first physical resource block comprising all subcarriers of atransmission bandwidth for the IoT communications and all orthogonalfrequency division multiplexed symbols of a first subframe fortransmission to a first UE.

Operation 305, meanwhile, is performed by the UE, which monitors signalson the first transmission bandwidth. As described above, the UE monitorsthe transmission bandwidth and attempts to identify one or morerepetitions of a control transmission. At some point during themonitoring, the UE receives the narrowband control channel transmissionfrom the eNB, with the transmission mapped to the entire physicalresource block comprising all subcarriers of the transmission bandwidthand all OFDM symbols of the subframe. In some embodiments, monitoring ison a first transmission bandwidth for a narrowband (e.g. IoT) systemwith the first transmission bandwidth comprising a single physicalresource block bandwidth.

The UE determines that the control channel transmission from the eNBincludes at least a first narrowband physical downlink control channel(NB-PDCCH) as a channel for communicating control signals that is mappedto a first physical resource block. This first physical resource blockincludes or otherwise covers all subcarriers of the transmissionbandwidth for the narrowband configuration. This does not necessarilyinclude all bandwith of the system, but all bandwidth of the narrowband(IoT) operation for communicating between the UE and the eNB. Thephysical resource block further operates using orthogonal frequencydivision multiplexed symbols of at least a first subframe.

The UE then takes to the received transmission and blind decodes thefirst control channel transmission from the eNB in operation 310. Insome embodiments, the decoding occurs through aggregation of multipletransmitted copies of the first physical resource block on the firsttransmission bandwidth. Such blocks may be consecutive ornon-consecutive in the time domain in various embodiments.

Once the control transmission is decoded, the UE extracts modulatedsymbols of the first control transmission according to a specifiedresource element grouping in operation 315. Resource elements of thespecified resource element grouping comprise one subcarrier of one OFDMsymbol. In some embodiments, the resource element grouping comprises onesubcarrier of one subframe.

Various alternative implementations of such a method may then bestructured in different ways. In one alternative embodiment, theresource element grouping is defined such that modulated symbols of thecontrol channel transmission are mapped to the dc subcarrier of the OFDMwaveform, with the resource element grouping being defined in pairs ofsubcarriers whereby within each pair the modulated symbols are mappedfrequency first and time second.

In another alternative embodiment, the resource element grouping isdefined in pairs of subcarriers whereby within each pair modulatedsymbols are mapped frequency first and time second. In some suchembodiments, the number of the resource element groups being fixedwithin one subframe and the number of resource elements in one resourceelement group are variable. In additional embodiments, the number of theresource element groups is variable within one subframe and the numberof resource elements in one resource element group is fixed or variable.In still further embodiments, the UE excludes certain resources from thephysical resource blocks.

FIG. 4 illustrates another method for control channel communications ina NB-IoT system, in accordance with embodiments described herein. Method400 is performed by a UE or similar device and may be implemented asinstructions in storage memory in various embodiments as describedabove.

In operation 405, said UE receives a narrowband control channeltransmission from an eNB and determines the resources available for thetransmission of said narrowband control channel.

In operation 410, said UE adapts the resource element grouping and/orthe aggregation resource element groups depending on the number ofavailable resources for the transmission of said narrowband controlchannel.

In various embodiments, method 400 may be performed with certainoperations of method 300 at the same UE. In other embodiments, method400 may be performed independently.

FIG. 5 illustrates another method for control channel communications ina NB-IoT system, in accordance with embodiments described herein. Method500 is performed by a UE or similar device and may be implemented asinstructions in storage memory in various embodiments as describedabove.

As part of method 500, a UE receives a narrowband control channeltransmission from an eNB in operation 505. The UE in operation 505 thendetermines resources available for the transmissions of the narrowbandcontrol channel. In various embodiments, the transmission may bereceived on one carrier or on multiple narrowband carriers.

The UE then performs determination and/or adaptation operations inoperation 510. As part of such operations, the UE may determine controlchannel characteristics, including the control channel starting symboland/or subframe of the associated data transmission. The UE may adaptresource element groupings. The UE may also aggregate resource elementgroups. Such aggregation may depend on a number of available resourcesfor transmission of the narrowband control channel.

In various implementations of such embodiments, the UE assumes that saidcontrol channel transmission is mapped to a subset of subcarriers of thetransmission bandwidth on all OFDM symbols of the subframe. In someembodiments, the UE monitors a subset of subcarriers of the transmissionbandwidth for possible control channel transmissions. In someembodiments, such a subset of subcarriers is signaled to the UE viasystem information broadcast or user equipment specific radio resourcecontrol signaling and/or said subset of subcarrier depending on thecoverage class/level of said UE. In further embodiments, the UE attemptsto decode said control channel transmission by aggregating multiplesubsets of subcarriers within a subframe. In still further embodiments,the modulated symbols of said control channel transmission are mapped tosaid subsets of subcarriers in a frequency first and time second manner.

For embodiments where the UE receives narrowband control channeltransmissions on multiple narrowband carriers, various differentimplementations may be used in different embodiments. In some suchembodiments, the narrowband carriers are specifically configured by auser. Some such embodiments operate with a separate configuration forthe user-specific and common search space. In other embodiments, the UEmonitors a subset of subcarriers of the transmission bandwidth forpossible control channel transmissions. In still further embodiments,the UE receives certain common control channel transmissions on adedicated narrowband carrier.

Some embodiments operate where the control channel transmissionsindicate to the UE on which narrowband carrier the UE is to receiveassociated data transmissions. In some embodiments, the narrowbandcarriers are broadcast in the system information, where the systeminformation indicates that additional system information can be receivedon a separate narrowband carrier. In some embodiments, the narrowbandcarrier(s) depend on the UE's channel conditions.

In various implementations of the methods described above, and thevariations and different implementations of the methods described above,particular operations may be repeated or performed in different ordersin accordance with different embodiments. Additionally, the operationsof different methods may be performed together or independently in anygrouping. In particular, certain embodiments are performed with anindividual UE performing all operations of the embodiment. Similarly,other embodiments are performed with an eNB performing all operations ofthe embodiment. A non-exhaustive list of example embodiments is detailedbelow.

Example Embodiments

Example 1 may include a method comprising: receiving a narrowbandcontrol channel transmission from an eNB and assuming that said controlchannel transmission is mapped to an entire physical resource blockcomprising all subcarriers of the transmission bandwidth and all OFDMsymbols of the subframe.

Example 2 may include a method of example 1 and/or other examplesherein, further comprising: attempting to decode said control channeltransmission by aggregating multiple physical resource blocks.

Example 3 may include a method of example 2 and/or other examplesherein, further comprising: said multiple physical resource blocks beingconsecutive in the time-domain.

Example 4 may include a method of example 2 and/or other examplesherein, further comprising: said multiple physical resource blocks notbeing consecutive in the time-domain.

Example 5 may include a method of example 1 and/or other examplesherein, further comprising: extracting the modulated symbols of thecontrol channel transmission according to a specified resource elementgrouping where a resource element comprises one subcarrier of one OFDMsymbol.

Example 6 may include a method of example 5 and/or other examplesherein, further comprising: said resource element grouping being definedas one subcarrier of one subframe.

Example 7 may include a method of example 6 and/or other examplesherein, further comprising: said resource element grouping being definedsuch that modulated symbols of the control channel transmission aremapped to the d subcarrier of the OFDM waveform.

Example 8 may include a method of example 6 and/or other examplesherein, further comprising: said resource element grouping being definedin pairs of subcarriers whereby within each pair modulated symbols aremapped frequency first and time second.

Example 9 may include a method of example 7 and/or other examplesherein, further comprising: said resource element grouping being definedin pairs of subcarriers whereby within each pair modulated symbols aremapped frequency first and time second.

Example 10 may include a method of example 1 and/or other examplesherein, further comprising: excluding certain resources from thephysical resource blocks.

Example 11 may include a method of example 5 and/or other examplesherein, further comprising: the number of said resource element groupsbeing fixed within one subframe and the number of resource elements inone resource element group being variable.

Example 12 may include a method of example 5 and/or other examplesherein, further comprising: the number of said resource element groupsbeing variable within one subframe and the number of resource elementsin one resource element group being fixed.

Example 13 may include a method of example 5 and/or other examplesherein, further comprising: the number of said resource element groupsbeing variable within one subframe and the number of resource elementsin one resource element group being variable.

Example 14 may include a method comprising: receiving a narrowbandcontrol channel transmission from an eNB; determining the resourcesavailable for the transmission of said narrowband control channel; andadapting the resource element grouping and/or the aggregation resourceelement groups depending on the number of available resources for thetransmission of said narrowband control channel.

Example 15 may include a method comprising: receiving a narrowbandcontrol channel transmission from an eNB, with said control channelindicating to the UE the starting symbol and/or subframe of theassociated data transmission.

Example 16 may include a method comprising: receiving a narrowbandcontrol channel transmission from an eNB and assuming that said controlchannel transmission is mapped to a subset of subcarriers of thetransmission bandwidth on all OFDM symbols of the subframe.

Example 17 may include a method of example 16 and/or other examplesherein, further comprising: monitoring a subset of subcarriers of thetransmission bandwidth for possible control channel transmissions.

Example 18 may include a method of example 17 and/or other examplesherein, further comprising: said subset being signaled via systeminformation broadcast on UE specific radio resource control signaling.

Example 19 may include a method of example 17 and/or other examplesherein, further comprising: said subset of subcarrier depending on thecoverage class/level of said UE.

Example 20 may include a method of example 16 and/or other examplesherein, further comprising: attempting to decode said control channeltransmission by aggregating multiple subsets of subcarriers within asubframe.

Example 21 may include a method of example 16 and/or other examplesherein, further comprising: modulated symbols of said control channeltransmission being mapped to said subsets of subcarriers in a frequencyfirst, time second manner.

Example 22 may include a method comprising: receiving narrowband controlchannel transmissions on multiple narrowband carriers.

Example 23 may include a method of example 22 and/or other examplesherein, further comprising: said narrowband carriers being userspecifically configured.

Example 24 may include a method of example 23 and/or other examplesherein, further comprising: a separate configuration for theuser-specific and common search space.

Example 25 may include a method of example 23 and/or other examplesherein, further comprising: receiving certain common control channeltransmissions on a dedicated narrowband carrier.

Example 26 may include a method of example 22 and/or other examplesherein, further comprising: said control channel transmissionsindicating on which narrowband carrier to receive associated datatransmissions.

Example 27 may include a method of example 22 and/or other examplesherein, further comprising: said narrowband carriers being broadcast inthe system information.

Example 28 may include a method of example 22 and/or other examplesherein, further comprising: the narrowband carrier(s) depending onchannel conditions of a UE.

Example 29 may include a method of example 27 and/or other examplesherein, further comprising: said system information indicating thatadditional system information can be received on a separate narrowbandcarrier.

Example 30 may include the method of any of examples 1-29, wherein themethod is performed by a UE or a portion thereof.

Example 31 may include the method of any of examples 1-29, wherein themethod is performed by an eNB or a portion thereof.

Example 32 may include inferring legacy Cell-Specific Reference Signalresources from a detected Physical Cell ID.

Example 33 may include example 32, wherein the inference is based on anarrowband secondary synchronization signal.

Example 34 may include any of example 32 or 33, wherein, afterdeterministically deriving the protected resources, rate matchingnarrowband Physical Downlink Control Channels.

Example 35 may include any of examples 1 to 34 or any other exampleherein, wherein the number of Resource Elements within a NarrowbandResource Element Group used for transmission of the Narrowband PhysicalDownlink Control Channels is constant.

Example 36 may include any of examples 1 to 35 or any other exampleherein, wherein multiple Narrowband Physical Downlink Control Channelsare multiplexed within one subframe.

Example 37 may include any of examples 1 to 36 or any other exampleherein, wherein a narrowband resource element group and/or narrowbandcontrol channel element definition may depend on a mode of operationsignaled by a narrowband primary synchronization signal, secondarysynchronization signal, or physical broadcast channel.

Example 38 may include any of examples 1 to 37 or any other exampleherein, wherein one narrowband control channel element corresponds toone physical resource block pair and/or wherein multiple narrowbandphysical downlink control channels are multiplexed in a time-divisionmultiplexing manner.

Example 39 may include any of examples 1 to 38 or any other exampleherein, wherein narrowband control channel elements comprise the entirephysical resource block.

Example 40 may include example 39, wherein the narrowband controlchannel elements are further sub-divided into narrowband resourceelement groups.

Example 41 may include example 40, wherein one narrowband resourceelement group comprises resource elements on a single subcarrier in agiven subframe.

Example 41 may include example 40, wherein modulated multiple narrowbandphysical downlink control channels are mapped to the dc subcarrier ofthe OFDM waveform.

Example 42 may include example 41, wherein a first-time mapping isperformed in pairs of sub-carriers and space frequency block codes areapplied to these pairs.

Example 43 may include an apparatus comprising radio frequency (RF)circuitry to receive a signal and baseband circuitry coupled with the RFcircuitry, with the baseband circuitry to process the signal; whichapparatus is configured to perform the method of any one of Example 1 toExample 42

Example 44 may include one or more non-transitory computer-readablemedia comprising instructions to cause an electronic device, uponexecution of the instructions by one or more processors of theelectronic device, to perform one or more elements of a method describedin or related to any of examples 1-42, or any other method or processdescribed herein.

Example 45 may include an apparatus comprising logic, modules, and/orcircuitry to perform one or more elements of a method described in orrelated to any of examples 1-42, or any other method or processdescribed herein.

Example 46 may include a method, technique, or process as described inor related to any of examples 1-42, or portions or parts thereof.

Example 47 may include an apparatus comprising: one or more processorsand one or more computer readable media comprising instructions that,when executed by the one or more processors, cause the one or moreprocessors to perform the method, techniques, or process as described inor related to any of examples 1-42, or portions thereof.

Example 48 may include a method of communicating in a wireless networkas shown and described herein.

Example 49 may include a system for providing wireless communication asshown and described herein.

Example 50 may include a device for providing wireless communication asshown and described herein.

Example 51 is an apparatus of a UE for narrowband Internet-of-Things(IoT) communication, the apparatus comprising: a memory; and processingcircuitry in communication with the memory and arranged to: monitorsignals on a first transmission bandwidth for a narrowband system withthe first transmission bandwidth comprising a single physical resourceblock bandwidth: determine that a control channel transmission from anevolved node B (eNB) comprising at least a first narrowband physicaldownlink control channel (NB-PDCCH) is mapped to a first physicalresource block including subcarriers of the transmission bandwidth andorthogonal frequency division multiplexed symbols of at least a firstsubframe; and blind decode the first control transmission comprising theNB-PDCCH by processing a first physical resource block including thesubcarriers of the transmission bandwidth and the orthogonal frequencydivision multiplexed symbols of the first subframe to determine thefirst control transmission.

In Example 52, the subject matter of Example 51 optionally includeswherein the processing circuitry is further configured to blind decodethe first control transmission from the eNB by processing a plurality offirst physical resource blocks, the plurality of physical resourceblocks comprising the first physical resource block, each physicalresource block of the plurality of resource blocks comprising allsubcarriers of the transmission bandwidth for corresponding timeperiods.

In Example 53, the subject matter of Example 52 optionally includeswherein the corresponding time periods for the plurality of physicalresource blocks are consecutive in the time domain.

In Example 54, the subject matter of any one or more of Examples 52-53optionally include wherein the corresponding time periods for theplurality of physical resource blocks are not all consecutive in thetime domain.

In Example 55, the subject matter of any one or more of Examples 52-54optionally include wherein the processing circuitry is furtherconfigured to extract modulated symbols of the first controltransmission according to a specified resource element grouping.

In Example 56, the subject matter of Example 55 optionally includeswherein a subcarrier of one orthogonal frequency division multiplexedsymbol comprises a resource element of the specified resource elementgrouping.

In Example 57, the subject matter of any one or more of Examples 55-56optionally includes wherein the specified resource element groupingcomprises a first subcarrier of a first subframe.

In Example 58, the subject matter of Example 57 optionally includeswherein the specified resource element grouping further comprisesmodulated symbols of the control channel transmission mapped to a directcurrent (DC) subcarrier of an OFDM waveform.

In Example 59, the subject matter of any one or more of Examples 57-58optionally includes wherein the specified resource element groupingcomprises pairs of subcarriers, each pair of subcarriers comprisingmodulated symbols with a first mapped frequency and a second mappedtime.

In Example 60, the subject matter of any one or more of Examples 56-59optionally includes, wherein the specified resource element groupingcomprises a plurality of resource element groups, wherein the pluralityof resource element groups is fixed in number within a first subframeand wherein the number of resource elements within each resource elementgroup of the plurality of resource element groups is variable.

In Example 61, the subject matter of any one or more of Examples 56-60optionally includes, wherein the specified resource element groupingcomprises a plurality of resource element groups, wherein the pluralityof resource element groups is variable in number within a first subframeand wherein the number of resource elements within each resource elementgroup of the plurality of resource element groups is fixed.

In Example 62, the subject matter of any one or more of Examples 56-61optionally includes, wherein the specified resource element groupingcomprises a plurality of resource element groups, wherein the pluralityof resource element groups is variable in number within a first subframeand wherein the number of resource elements within each resource elementgroup of the plurality of resource element groups is variable.

In Example 63, the subject matter of any one or more of Examples 51-62optionally includes further comprising: an antenna coupled to theprocessing circuitry, the antenna configured to receive the signals onthe first transmission bandwidth and transmit the signals to theprocessing circuitry.

Example 64 is a computer-readable storage medium that storesinstructions for execution by one or more processors of a UE, the one ormore processors to configure the UE to: monitor signals on a firsttransmission bandwidth; blind decode a first control transmission froman evolved node B (eNB) by processing a first physical resource blockcomprising all subcarriers of the transmission bandwidth and allorthogonal frequency division multiplexed symbols of a first subframe todetermine the first control transmission, wherein first controltransmission is further decoded according to a specified resourceelement grouping.

In Example 65, the subject matter of Example 64 optionally includeswherein a subcarrier of one orthogonal frequency division multiplexedsymbol comprises a resource element of the specified resource elementgrouping.

In Example 66, the subject matter of Example 65 optionally includeswherein the specified resource element grouping comprises a firstsubcarrier of a first subframe; and wherein the specified resourceelement grouping further comprises modulated symbols of the controlchannel transmission mapped to a direct current (DC) subcarrier of anOFDM waveform.

In Example 67, the subject matter of any one or more of Examples 65-66optionally includes wherein the specified resource element groupingcomprises pairs of subcarriers, each pair of subcarriers comprisingmodulated symbols with a first mapped frequency and a second mappedtime.

In Example 68, the subject matter of any one or more of Examples 65-67optionally includes, wherein the specified resource element groupingcomprises a plurality of resource element groups, wherein the pluralityof resource element groups is fixed in number within a first subframeand wherein the number of resource elements within each resource elementgroup of the plurality of resource element groups is variable.

In Example 69, the subject matter of any one or more of Examples 65-68optionally includes, wherein the specified resource element groupingcomprises a plurality of resource element groups, wherein the pluralityof resource element groups is variable in number within a first subframeand wherein the number of resource elements within each resource elementgroup of the plurality of resource element groups is variable.

Example 70 is an apparatus of an evolved node B (eNB) for encodingcontrol channel signals for narrowband Internet-of-Things (IoT)communications, the apparatus comprising: a memory; and processingcircuitry in communication with the memory and arranged to: encode afirst control transmission using a first physical resource blockcomprising all subcarriers of a transmission bandwidth for the IoTcommunications and all orthogonal frequency division multiplexed symbolsof a first subframe for transmission to a first UE.

In Example 71, the subject matter of Example 70 optionally includeswherein the processing circuitry is further configured to encode thefirst control transmission from the eNB to the UE using a plurality ofphysical resource blocks, the plurality of physical resource blockscomprising the first physical resource block, each physical resourceblock of the plurality of resource blocks comprising all subcarriers ofthe transmission bandwidth for corresponding time periods.

In Example 72, the subject matter of Example 71 optionally includeswherein the corresponding time periods for the plurality of physicalresource blocks are not all consecutive in the time domain.

In Example 73, the subject matter of any one or more of Examples 71-72optionally includes wherein the processing circuitry is furtherconfigured to encode the first control transmission according tospecified resource element groupings comprising a plurality of resourceelement groups, each resource element group of the plurality of resourceelement groups comprising one or more resource elements.

In Example 74, the subject matter of Example 73 optionally includeswherein the specified resource element grouping comprises a firstsubcarrier of a first subframe; and wherein the specified resourceelement grouping further comprises modulated symbols of the controlchannel transmission mapped to a direct current (DC) subcarrier of anOFDM waveform.

In Example 75, the subject matter of any one or more of Examples 71-74optionally includes, wherein the plurality of resource element groupsare fixed in number within a first subframe and wherein the number ofresource elements within each resource element group of the plurality ofresource element groups is variable.

Example 76 is an apparatus of a user equipment (UE) for narrowbandInternet-of-Things (NB-IoT) communication, the apparatus comprising:processor means for monitoring signals on a first transmission bandwidthfor a narrowband system with the first transmission bandwidth comprisinga single physical resource block bandwidth; processor means fordetermining that a control channel transmission from an evolved node B(eNB) comprising at least a first narrowband physical downlink controlchannel (NB-PDCCH) is mapped to a first physical resource blockincluding subcarriers of the transmission bandwidth and orthogonalfrequency division multiplexed symbols of at least a first subframe: andprocessor means for blind decoding the first control transmissioncomprising the NB-PDCCH by processing a first physical resource blockincluding the subcarriers of the transmission bandwidth and theorthogonal frequency division multiplexed symbols of the first subframeto determine the first control transmission.

In Example 77, the subject matter of Example 76 optionally includes,wherein the first control transmission from the eNB by processing aplurality of physical resource blocks, the plurality of physicalresource blocks comprising the first physical resource block, eachphysical resource block of the plurality of resource blocks comprisingall subcarriers of the transmission bandwidth for corresponding timeperiods.

In Example 78, the subject matter of Example 77 optionally includes,wherein the corresponding time periods for the plurality of physicalresource blocks are consecutive in time domain.

In Example 79, the subject matter of any one or more of Examples 77-78optionally include, wherein the corresponding time periods for theplurality of physical resource blocks are not all consecutive in timedomain.

In Example 80, the subject matter of any one or more of Examples 77-79optionally include, wherein the processing circuitry is furtherconfigured to extract modulated symbols of the first controltransmission according to a specified resource element grouping.

In Example 81, the subject matter of Example 80 optionally includes,wherein a subcarrier of one orthogonal frequency division multiplexedsymbol comprises a resource element of the specified resource elementgrouping.

Example 82 is a method performed by an apparatus of a user equipment(UE), the method comprising: monitoring signals on a first transmissionbandwidth for a narrowband system with the first transmission bandwidthcomprising a single physical resource block bandwidth; determining thata control channel transmission from an evolved node B (eNB) comprisingat least a first narrowband physical downlink control channel (NB-PDCCH)is mapped to a first physical resource block including subcarriers ofthe transmission bandwidth and orthogonal frequency division multiplexedsymbols of at least a first subframe: and blind decoding the firstcontrol transmission comprising the NB-PDCCH by processing a firstphysical resource block including the subcarriers of the transmissionbandwidth and the orthogonal frequency division multiplexed symbols ofthe first subframe to determine the first control transmission.

In Example 83, the subject matter of Example 82 optionally includes,wherein a subcarrier of one orthogonal frequency division multiplexedsymbol comprises a resource element of the specified resource elementgrouping.

In Example 84, the subject matter of Example 83 optionally includes,wherein the specified resource element grouping comprises a firstsubcarrier of a first subframe; and wherein the specified resourceelement grouping further comprises modulated symbols of the controlchannel transmission mapped to a direct current (DC) subcarrier of anorthogonal frequency division multiplexing (OFDM) waveform.

In Example 85, the subject matter of Example 84 optionally includes,wherein the specified resource element grouping comprises pairs ofsubcarriers, each pair of subcarriers comprising modulated symbols witha first mapped frequency and a second mapped time.

In Example 86, the subject matter of any one or more of Examples 84-85optionally include, wherein the specified resource element groupingcomprises a plurality of resource element groups, wherein the pluralityof resource element groups are fixed in number within a first subframe;and wherein the number of resource elements within each resource elementgroup of the plurality of resource element groups is variable.

In Example 87, the subject matter of any one or more of Examples 84-86optionally include, wherein the specified resource element groupingcomprises a plurality of resource element groups, wherein the pluralityof resource element groups are variable in number within a firstsubframe: and wherein the number of resource elements within eachresource element group of the plurality of resource element groups isvariable.

Example 88 is an apparatus of an evolved node B (eNB) for encodingcontrol channel signals for narrowband Internet-of-Things (IoT)communications, the apparatus comprising: means for encoding a firstcontrol transmission using a first physical resource block comprisingall subcarriers of a transmission bandwidth for the IoT communicationsand all orthogonal frequency division multiplexed symbols of a firstsubframe for transmission to a first user equipment (UE).

In Example 89, the subject matter of Example 88 optionally includes,wherein the first control transmission from the eNB to the UE is encodedusing a plurality of physical resource blocks, the plurality of physicalresource blocks comprising the first physical resource block, eachphysical resource block of the plurality of resource blocks comprisingall subcarriers of the transmission bandwidth for corresponding timeperiods.

In Example 90, the subject matter of Example 89 optionally includes,wherein the corresponding time periods for the plurality of physicalresource blocks are not all consecutive in the time domain.

In Example 91, the subject matter of any one or more of Examples 89-90optionally include, wherein the processing circuitry is furtherconfigured to encode the first control transmission according tospecified resource element groupings comprising a plurality of resourceelement groups, each resource element group of the plurality of resourceelement groups comprising one or more resource elements.

Example 92 is a method performed by an evolved Node B (eNB) in acommunication system, the method comprising: encoding a control channeltransmission for a first user equipment (UE), the control channeltransmission comprising at least a first narrowband physical downlinkcontrol channel (NB-PDCCH) is mapped to a first physical resource blockincluding subcarriers of the transmission bandwidth and orthogonalfrequency division multiplexed symbols of at least a first subframe forblind decoding at the UE via processing a first physical resource blockincluding the subcarriers of the transmission bandwidth and theorthogonal frequency division multiplexed symbols of the first subframeto determine the first control transmission; and initiate transmissionof the NB-PDCCH to the first UE.

In Example 93, the subject matter of Example 92 optionally includeswherein the first control transmission is encoded according to specifiedresource element groupings comprising a plurality of resource elementgroups, each resource element group of the plurality of resource elementgroups comprising one or more resource elements; wherein the specifiedresource element grouping comprises a first subcarrier of a firstsubframe; and wherein the specified resource element grouping furthercomprises modulated symbols of the control channel transmission mappedto a direct current (DC) subcarrier of an orthogonal frequency divisionmultiplexing (OFDM) waveform.

In Example 94, the subject matter of any one or more of Examples 92-93optionally include, wherein the plurality of resource element groups arefixed in number within a first subframe; and wherein the number ofresource elements within each resource element group of the plurality ofresource element groups is variable.

FIG. 6 shows an example UE, illustrated as a UE 600. The UE 600 may bean implementation of the UE 82, or any device described herein. The UE600 can include one or more antennas 608 configured to communicate witha transmission station, such as a base station (BS), an eNB, or anothertype of wireless wide area network (WWAN) access point. The UE 600 canbe configured to communicate using at least one wireless communicationstandard including 3GPP LTE, WiMAX, High Speed Packet Access (ISPA),Bluetooth, and WiFi. The UE 600 can communicate using separate antennasfor each wireless communication standard or shared antennas for multiplewireless communication standards. The UE 600 can communicate in a WLAN,a wireless personal area network (WPAN), and/or a WWAN.

FIG. 6 also shows a microphone 620 and one or more speakers 612 that canbe used for audio input and output to and from the UE 600. A displayscreen 604 can be a liquid crystal display (LCD) screen, or another typeof display screen such as an organic light emitting diode (OLED)display. The display screen 604 can be configured as a touch screen. Thetouch screen can use capacitive, resistive, or another type of touchscreen technology. An application processor 614 and a graphics processor618 can be coupled to an internal memory 616 to provide processing anddisplay capabilities. A non-volatile memory port 610 can also be used toprovide data I/O options to a user. The non-volatile memory port 610 canalso be used to expand the memory capabilities of the UE 600. A keyboard606 can be integrated with the UE 600 or wirelessly connected to the UE600 to provide additional user input. A virtual keyboard can also beprovided using the touch screen. A camera 622 located on the front(display screen) side or the rear side of the UE 600 can also beintegrated into a housing 602 of the UE 600.

FIG. 7 is a block diagram illustrating an example computer systemmachine 700 upon which any one or more of the methodologies hereindiscussed can be run, and which may be used to implement the eNB 84, theUE 82, or any other device described herein. In various alternativeembodiments, the machine operates as a standalone device or can beconnected (e.g., networked) to other machines. In a networkeddeployment, the machine can operate in the capacity of either a serveror a client machine in server-client network environments, or it can actas a peer machine in peer-to-peer (or distributed) network environments,the machine can be a personal computer (PC) that may or may not beportable (e.g., a notebook or a netbook), a tablet, a set-top box (STB),a gaming console, a Personal Digital Assistant (PDA), a mobile telephoneor smartphone, a web appliance, a network router, a network switch, anetwork bridge, or any machine capable of executing instructions(sequential or otherwise) that specify actions to be taken by thatmachine. Further, while only a single machine is illustrated, the term“machine” shall also be taken to include any collection of machines thatindividually or jointly execute a set (or multiple sets) of instructionsto perform any one or more of the methodologies discussed herein.

The example computer system machine 700 includes a processor 702 (e.g.,a central processing unit (CPU), a graphics processing unit (GPU), orboth), a main memory 704, and a static memory 706, which communicatewith each other via an interconnect 708 (e.g., a link, a bus, etc.) Thecomputer system machine 700 can further include a video display unit710, an alphanumeric input device 712 (e.g., a keyboard), and a userinterface (UI) navigation device 714 (e.g., a mouse). In one embodiment,the video display unit 710, alphanumeric input device 712, and UInavigation device 714 are a touch screen display. The computer systemmachine 700 can additionally include a mass storage device 716 (e.g., adrive unit), a signal generation device 718 (e.g., a speaker), an outputcontroller 732, a power management controller 734, a network interfacedevice 720 (which can include or operably communicate with one or moreantennas 730, transceivers, or other wireless communications hardware),and one or more sensors 728, such as a GPS sensor, compass, locationsensor, accelerometer, or other sensor.

The mass storage device 716 includes a machine-readable medium 722 onwhich is stored one or more sets of data structures and instructions 724(e.g., software) embodying or utilized by any one or more of themethodologies or functions described herein. The instructions 724 canalso reside, completely or at least partially, within the main memory704, static memory 706, and/or processor 702 during execution thereof bythe computer system machine 700, with the main memory 704, the staticmemory 706, and the processor 702 also constituting machine-readablemedia.

While the machine-readable medium 722 is illustrated in an exampleembodiment to be a single medium, the term “machine-readable medium” caninclude a single medium or multiple media (e.g., a centralized ordistributed database, and/or associated caches and servers) that storethe one or more instructions 724. The term “machine-readable medium”shall also be taken to include any tangible medium that is capable ofstoring, encoding, or carrying to instructions for execution by themachine and that cause the machine to perform any one or more of themethodologies of the present disclosure, or that is capable of storing,encoding, or carrying data structures utilized by or associated withsuch instructions.

The instructions 724 can further be transmitted or received over acommunications network 726 using a transmission medium via the networkinterface device 720 utilizing any one of a number of well-knowntransfer protocols (e.g., hypertext transfer protocol (HTTP)). The term“transmission medium” shall be taken to include any medium that iscapable of storing, encoding, or carrying instructions for execution bythe machine, and includes digital or analog communications signals orother intangible media to facilitate communication of such software.

Various techniques, or certain aspects or portions thereof may take theform of program code (i.e., instructions) embodied in tangible media,such as floppy diskettes, CD-ROMs, hard drives, non-transitory computerreadable storage media, or any other machine-readable storage mediumwherein, when the program code is loaded into and executed by a machine,such as a computer, the machine becomes an apparatus for practicing thevarious techniques. In the case of program code execution onprogrammable computers, the computing device may include a processor, astorage medium readable by the processor (including volatile andnon-volatile memory and/or storage elements), at least one input device,and at least one output device. The volatile and non-volatile memoryand/or storage elements may be a Random Access Memory (RAM). ErasableProgrammable Read-Only Memory (EPROM), flash drive, optical drive,magnetic hard drive, or other medium for storing electronic data. TheeNB and UE may also include a transceiver module, a counter module, aprocessing module, and/or a clock module or timer module. One or moreprograms that may implement or utilize the various techniques describedherein may use an application programming interface (API), reusablecontrols, and the like. Such programs may be implemented in a high-levelprocedural or object-oriented programming language to communicate with acomputer system. However, the program(s) may be implemented in assemblyor machine language, if desired. In any case, the language may be acompiled or interpreted to language, and combined with hardwareimplementations.

Various embodiments may use 3GPP LTE/LTE-A, Institute of Electrical andElectronic Engineers (IEEE) 702.11, and Bluetooth communicationstandards. Various alternative embodiments may use a variety of otherWWAN. WLAN, and WPAN protocols and standards in connection with thetechniques described herein. These standards include, but are notlimited to, other standards from 3GPP (e.g., HSPA+, UMTS), IEEE 702.16(e.g., 702.16p), or Bluetooth (e.g., Bluetooth 6.0, or like standardsdefined by the Bluetooth Special Interest Group) standards families.Other applicable network configurations can be included within the scopeof the presently described communication networks. It will be understoodthat communications on such communication networks can be facilitatedusing any number of personal area networks (PANs), local area networks(LANs), and wide area networks (WANs), using any combination of wired orwireless transmission mediums.

Embodiments described herein may be implemented into a system using anysuitably configured hardware and/or software. FIG. 8 illustratescomponents of a UE 800, in accordance with some embodiments. At leastsome of the components shown may be used in the UE 82 (or eNB 84) shownin FIG. 1. The UE 800 and other components may be configured to use thesynchronization signals as described herein. The UE 800 may be one ofthe UEs 82 shown in FIG. 1 and may be a stationary, non-mobile device ormay be a mobile device. In some embodiments, the UE 800 may includeapplication circuitry 802, baseband circuitry 804, Radio Frequency (RF)circuitry 806, front-end module (FEM) circuitry 808, and one or moreantennas 810, coupled together at least as shown. At least some of thebaseband circuitry 804, RF circuitry 806, and FEM circuitry 808 may forma transceiver. In some embodiments, other network elements, such as theeNB 84, may contain some or all of the components shown in FIG. 8. Otherof the network elements, such as the MME, may contain an interface, suchas the S1 interface, to communicate with the eNB over a wired connectionregarding the UE 800.

The application circuitry 802 may include one or more applicationprocessors. For example, the application circuitry 802 may includecircuitry such as, but not limited to, one or more single-core ormulti-core processors. The processor(s) may include any combination ofgeneral-purpose processors and dedicated processors (e.g., graphicsprocessors, application processors, etc.). The processors may be coupledwith and/or may include memory/storage and may be configured to executeinstructions stored in the memory/storage to enable various applicationsand/or operating systems to run on the UE 800.

The baseband circuitry 804 may include circuitry such as, but notlimited to, one or more single-core or multi-core processors. Thebaseband circuitry 804 may include one or more baseband processorsand/or control logic to process baseband signals received from a receivesignal path of the RF circuitry 806 and to generate baseband signals fora transmit signal path of the RF circuitry 806. The baseband circuitry804 may interface with the application circuitry 802 for generation andprocessing of the baseband signals and for controlling operations of theRF circuitry 806. For example, in some embodiments, the basebandcircuitry 804 may include a second generation (2G) baseband processor804 a, third generation (3G) baseband processor 804 b, fourth generation(4G) baseband processor 804 c, and/or other baseband processor(s) 804 dfor other existing generations, generations in development, orgenerations to be developed in the future (e.g., fifth generation (5G),etc.). The baseband circuitry 804 (e.g., one or more of the basebandprocessors 804 a-d) may handle various radio control functions thatenable communication with one or more radio networks via the RFcircuitry 806. The radio control functions may include, but are notlimited to, signal modulation/demodulation, encoding/decoding, radiofrequency shifting, etc. In some embodiments, modulation/demodulationcircuitry of the baseband circuitry 804 may include FFT, precoding,and/or constellation mapping/demapping functionality. In someembodiments, encoding/decoding circuitry of the baseband circuitry 804may include convolution, tail-biting convolution, turbo, Viterbi, and/orLow Density Parity Check (LDPC) encoder/decoder functionality.Embodiments of modulation/demodulation and encoder/decoder functionalityare not limited to these examples and may include other suitablefunctionality in other embodiments.

In some embodiments, the baseband circuitry 804 may include elements ofa protocol stack such as, for example, elements of an evolved universalterrestrial radio access network (EUTRAN) protocol including, forexample, physical (PHY), media access control (MAC), radio link control(RLC), packet data convergence protocol (PDCP), and/or radio resourcecontrol (RRC) elements. A central processing unit (CPU) 804 e of thebaseband circuitry 804 may be configured to run elements of the protocolstack for signaling of the PHY, MAC, RLC, PDCP, and/or RRC layers. Insome embodiments, the baseband circuitry 804 may include one or moreaudio digital signal processor(s) (DSPs) 804 f. The audio DSP(s) 804 fmay be or include elements for compression/decompression and echocancellation and may include other suitable processing elements in otherembodiments. Components of the baseband circuitry 804 may be suitablycombined in a single chip or a single chipset, or disposed on a samecircuit board in some embodiments. In some embodiments, some or all ofthe constituent components of the baseband circuitry 804 and theapplication circuitry 802 may be implemented together, such as, forexample, on a system on a chip (SOC).

In some embodiments, the baseband circuitry 804 may provide forcommunication compatible with one or more radio technologies. Forexample, in some embodiments, the baseband circuitry 804 may supportcommunication with an EUTRAN and/or other wireless metropolitan areanetworks (WMAN), a WLAN, or a WPAN. Embodiments in which the basebandcircuitry 804 is configured to support radio communications of more thanone wireless protocol may be referred to as multi-mode basebandcircuitry. In some embodiments, the UE 800 can be configured to operatein accordance with communication standards or other protocols orstandards, including Institute of Electrical and Electronic Engineers(IEEE) 602.16 wireless technology (WiMax), IEEE 602.11 wirelesstechnology (WiFi) including IEEE 602.11 ad, which operates in the 60 GHzmillimeter wave spectrum, or various other wireless technologies such asglobal system for mobile communications (GSM), enhanced data rates forGSM evolution (EDGE). GSM EDGE radio access network (GERAN), universalmobile telecommunications system (UMTS), UMTS terrestrial radio accessnetwork (UTRAN), or other 2G, 3G, 4G, 5G, and the like technologieseither already developed or to be developed.

The RF circuitry 806 may enable communication with wireless networksusing modulated electromagnetic radiation through a non-solid medium. Invarious embodiments, the RF circuitry 806 may include switches, filters,amplifiers, and the like to facilitate the communication with thewireless network. The RF circuitry 806 may include a receive signalpath, which may include circuitry to down-convert RF signals receivedfrom the FEM circuitry 808 and provide baseband signals to the basebandcircuitry 804. The RF circuitry 806 may also include a transmit signalpath, which may include circuitry to up-convert baseband signalsprovided by the baseband circuitry 804 and provide RF output signals tothe FEM circuitry 808 for transmission.

In some embodiments, the RF circuitry 806 may include a receive signalpath and a transmit signal path. The receive signal path of the RFcircuitry 806 may include mixer circuitry 806 a, amplifier circuitry 806b, and filter circuitry 806 c. The transmit signal path of the RFcircuitry 806 may include the filter circuitry 806 c and the mixercircuitry 806 a. The RF circuitry 806 may also include synthesizercircuitry 806 d for synthesizing a frequency for use by the mixercircuitry 806 a of the receive signal path and the transmit signal path.In some embodiments, the mixer circuitry 806 a of the receive signalpath may be configured to down-convert RF signals received from the FEMcircuitry 808 based on the synthesized frequency provided by thesynthesizer circuitry 806 d. The amplifier circuitry 806 b may beconfigured to amplify the down-converted signals, and the filtercircuitry 806 c may be a low-pass filter (LPF) or band-pass filter (BPF)configured to remove unwanted signals from the down-converted signals togenerate output baseband signals. Output baseband signals may beprovided to the baseband circuitry 804 for further processing. In someembodiments, the output baseband signals may be zero-frequency basebandsignals, although this is not a requirement. In some embodiments, themixer circuitry 806 a of the receive signal path may comprise passivemixers, although the scope of the embodiments is not limited in thisrespect.

In some embodiments, the mixer circuitry 806 a of the transmit signalpath may be configured to up-convert input baseband signals based on thesynthesized frequency provided by the synthesizer circuitry 806 d togenerate RF output signals for the FEM circuitry 808. The basebandsignals may be provided by the baseband circuitry 804 and may befiltered by the filter circuitry 806 c. The filter circuitry 806 c mayinclude a low-pass filter (LPF), although the scope of the embodimentsis not limited in this respect.

In some embodiments, the mixer circuitry 806 a of the receive signalpath and the mixer circuitry 806 a of the transmit signal path mayinclude two or more mixers and may be arranged for quadraturedownconversion and/or upconversion respectively. In some embodiments,the mixer circuitry 806 a of the receive signal path and the mixercircuitry 806 a of the transmit signal path may include two or moremixers and may be arranged for image rejection (e.g., Hartley imagerejection). In some embodiments, the mixer circuitry 806 a of thereceive signal path and the mixer circuitry 806 a of the transmit signalpath may be arranged for direct downconversion and/or directupconversion, respectively. In some embodiments, the mixer circuitry 806a of the receive signal path and the mixer circuitry 806 a of thetransmit signal path may be configured for super-heterodyne operation.

In some embodiments, the output baseband signals and the input basebandsignals may be analog baseband signals, although the scope of theembodiments is not limited in this respect. In some alternateembodiments, the output baseband signals and the input baseband signalsmay be digital baseband signals. In these alternate embodiments, the RFcircuitry 806 may include analog-to-digital converter (ADC) anddigital-to-analog converter (DAC) circuitry, and the baseband circuitry804 may include a digital baseband interface to communicate with the RFcircuitry 806.

In some dual-mode embodiments, a separate radio IC circuitry may beprovided for processing signals for each spectrum, although the scope ofthe embodiments is not limited in this respect.

In some embodiments, the synthesizer circuitry 806 d may be afractional-N synthesizer or a fractional N/N+1 synthesizer, although thescope of the embodiments is not limited in this respect, as other typesof frequency synthesizers may be suitable. For example, the synthesizercircuitry 806 d may be a delta-sigma synthesizer, a frequencymultiplier, or a synthesizer comprising a phase-locked loop with afrequency divider.

The synthesizer circuitry 806 d may be configured to synthesize anoutput frequency for use by the mixer circuitry 806 a of the RFcircuitry 806 based on a frequency input and a divider control input. Insome embodiments, the synthesizer circuitry 806 d may be a fractionalN/N+1 synthesizer.

In some embodiments, frequency input may be provided by a voltagecontrolled oscillator (VCO), although that is not a requirement. Dividercontrol input may be provided by either the baseband circuitry 804 orthe application circuitry 802 depending on the desired output frequency.In some embodiments, a divider control input (e.g., N) may be determinedfrom a look-up table based on a channel indicated by the applicationcircuitry 802.

The synthesizer circuitry 806 d of the RF circuitry 806 may include adivider, a delay-locked loop (DLL), a multiplexer, and a phaseaccumulator. In some embodiments, the divider may be a dual modulusdivider (DMD) and the phase accumulator may be a digital phaseaccumulator (DPA). In some embodiments, the DMD may be configured todivide the input signal by either N or N+1 (e.g., based on a carry out)to provide a fractional division ratio. In some example embodiments, theDLL may include a set of cascaded, tunable, delay elements, a phasedetector, a charge pump, and a D-type flip-flop. In these embodiments,the delay elements may be configured to break a VCO period up into Ndequal packets of phase, where Nd is the number of delay elements in thedelay line. In this way, the DLL provides negative feedback to helpensure that the total delay through the delay line is one VCO cycle.

In some embodiments, the synthesizer circuitry 806 d may be configuredto generate a carrier frequency as the output frequency, while in otherembodiments, the output frequency may be a multiple of the carrierfrequency (e.g., twice the carrier frequency, four times the carrierfrequency) and used in conjunction with quadrature generator and dividercircuitry to generate multiple signals at the carrier frequency withmultiple different phases with respect to each other. In someembodiments, the output frequency may be a LO frequency (f_(LO)). Insome embodiments, the RF circuitry 806 may include an IQ/polarconverter.

The FEM circuitry 808 may include a receive signal path, which mayinclude circuitry configured to operate on RF signals received from theone or more antennas 810, amplify the received signals, and provide theamplified versions of the received signals to the RF circuitry 806 forfurther processing. The FEM circuitry 808 may also include a transmitsignal path which may include circuitry configured to amplify signalsfor transmission provided by the RF circuitry 806 for transmission byone or more of the one or more antennas 810.

In some embodiments, the FEM circuitry 808 may include a Tx/Rx switch toswitch between transmit mode and receive mode operation. The FEMcircuitry 808 may include a receive signal path and a transmit signalpath. The receive signal path of the FEM circuitry 808 may include alow-noise amplifier (LNA) to amplify received RF signals and provide theamplified received RF signals as an output (e.g., to the RF circuitry806). The transmit signal path of the FEM circuitry 808 may include apower amplifier (PA) to amplify input RF signals (e.g., provided by theRF circuitry 806), and one or more filters to generate RF signals forsubsequent transmission (e.g., by one or more of the one or moreantennas 810).

In some embodiments, the UE 800 may include additional elements such as,for example, a memory/storage, display, camera, sensor, and/orinput/output (I/O) interface as described in more detail below. In someembodiments, the UE 800 described herein may be part of a portablewireless communication device, such as a personal digital assistant(PDA), a laptop or portable computer with wireless communicationcapability, a web tablet, a wireless telephone, a smartphone, a wirelessheadset, a pager, an instant messaging device, a digital camera, anaccess point, a television, a medical device (e.g., a heart ratemonitor, a blood pressure monitor, etc.), or another device that mayreceive and/or transmit information wirelessly. In some embodiments, theUE 800 may include one or more user interfaces designed to enable userinteraction with the system and/or peripheral component interfacesdesigned to enable peripheral component interaction with the system. Forexample, the UE 800 may include one or more of a keyboard, a keypad, atouchpad, a display, a sensor, a non-volatile memory port, a universalserial bus (USB) port, an audio jack, a power supply interface, one ormore antennas, a graphics processor, an application processor, aspeaker, a microphone, and other I/O components. The display may be anLCD or LED screen including a touch screen. The sensor may include agyro sensor, an accelerometer, a proximity sensor, an ambient lightsensor, and a positioning unit. The positioning unit may communicatewith components of a positioning network, e.g., a global positioningsystem (GPS) satellite.

The antennas 810 may comprise one or more directional or omnidirectionalantennas, including, for example, dipole antennas, monopole antennas,patch antennas, loop antennas, microstrip antennas, or other types ofantennas suitable for transmission of RF signals. In some multiple-inputmultiple-output (MIMO) embodiments, the antennas 810 may be effectivelyseparated to take advantage of spatial diversity and the differentchannel characteristics that may result.

Although the UE 800 is illustrated as having several separate functionalelements, one or more of the functional elements may be combined and maybe implemented by combinations of software-configured elements, such asprocessing elements including digital signal processors (DSPs), and/orother hardware elements. For example, some elements may comprise one ormore microprocessors. DSPs, field-programmable gate arrays (FPGAs),application specific integrated circuits (ASICs), radio-frequencyintegrated circuits (RFICs), and combinations of various hardware andlogic circuitry for performing at least the functions described herein.In some embodiments, the functional elements may refer to one or moreprocesses operating on one or more processing elements.

Examples, as described herein, may include, or may operate on, logic ora number of components, modules, or mechanisms. Modules are tangibleentities (e.g., hardware) capable of performing specified operations andmay be configured or arranged in a certain manner. In an example,circuits may be arranged (e.g., internally or with respect to externalentities such as other circuits) in a specified manner as a module. Inan example, the whole or part of one or more computer systems (e.g., astandalone, client, or server computer system) or one or more hardwareprocessors may be configured by firmware or software (e.g.,instructions, an application portion, or an application) as a modulethat operates to perform specified operations. In an example, thesoftware may reside on a communication device-readable medium. In anexample, the software, when executed by the underlying hardware of themodule, causes the hardware to perform the specified operations.

Accordingly, the term “module” is understood to encompass a tangibleentity, be that an entity that is physically constructed, specificallyconfigured (e.g., hardwired), or temporarily (e.g., transitorily)configured (e.g., programmed) to operate in a specified manner or toperform part or all of any operation described herein. Consideringexamples in which modules are temporarily configured, each of themodules need not be instantiated at any one moment in time. For example,where the modules comprise a general-purpose hardware processorconfigured using software, the general-purpose hardware processor may beconfigured as respective different modules at different times. Softwaremay accordingly configure a hardware processor, for example, toconstitute a particular module at one instance of time and to constitutea different module at a different instance of time.

While the communication device-readable medium is illustrated as asingle medium, the term “communication device-readable medium” mayinclude a single medium or multiple media (e.g., a centralized ordistributed database, and/or associated caches and servers) configuredto store the one or more instructions.

The term “communication device-readable medium” may include any mediumthat is capable of storing, encoding, or carrying instructions forexecution by the communication device and that cause the communicationdevice to perform any one or more of the techniques of the presentdisclosure, or that is capable of storing, encoding, or carrying datastructures used by or associated with such instructions. Non-limitingcommunication device-readable medium examples may include solid-statememories, and optical and magnetic media. Specific examples ofcommunication device-readable media may include: non-volatile memory,such as semiconductor memory devices (e.g., EPROM, Electrically ErasableProgrammable Read-Only Memory (EEPROM)) and flash memory devices;magnetic disks, such as internal hard disks and removable disks;magneto-optical disks: RAM; and CD-ROM and DVD-ROM disks. In someexamples, communication device-readable media may include non-transitorycommunication device-readable media. In some examples, communicationdevice-readable media may include communication device-readable mediathat is not a transitory propagating signal.

The instructions may further be transmitted or received over acommunications network using a transmission medium via a networkinterface device utilizing any one of a number of transfer protocols(e.g., frame relay, internet protocol (TP), transmission controlprotocol (TCP), user datagram protocol (UDP), hypertext transferprotocol (HTTP), etc.). Example communication networks may include aLAN, a WAN, a packet data network (e.g., the Internet), mobile telephonenetworks (e.g., cellular networks), Plain Old Telephone (POTS) networks,and wireless data networks (e.g., Institute of Electrical andElectronics Engineers (IEEE) 602.11 family of standards known as Wi-Fi®,IEEE 602.16 family of standards known as WiMax®), IEEE 602.15.4 familyof standards, a Long Term Evolution (LTE) family of standards, aUniversal Mobile Telecommunications System (UMTS) family of standards,or peer-to-peer (P2P) networks, among others. In an example, the networkinterface device may include one or more physical jacks (e.g., Ethernet,coaxial, or phone jacks) or one or more antennas to connect to thecommunications network. In an example, the network interface device mayinclude a plurality of antennas to wirelessly communicate usingsingle-input multiple-output (SIMO), MIMO, or multiple-inputsingle-output (MISO) techniques. In some examples, the network interfacedevice may wirelessly communicate using Multiple User MIMO techniques.The term “transmission medium” shall be taken to include any intangiblemedium that is capable of storing, encoding, or carrying instructionsfor execution by the communication device, and includes digital oranalog communications signals or other intangible media to facilitatecommunication of such software.

As discussed above, an eNB may have multiple antennas that may be usedin various groupings and with various signal modifications for eachgrouping to produce a plurality of APs. Each AP may be defined for oneor more antennas. Each AP may correspond to a different transmissionsignal direction. Using the different APs, the eNB may transmit multiplelayers with codebook-based or non-codebook-based precoding techniques.Each AP may correspond to a beam that transmits AP-specific CSI-RSsignals. The UE may contain a plurality of receive antennas that may beused selectively to create Rx beamforming. Rx beamforming may be used toincrease the receive antenna (beamforming) gain for the direction(s) onwhich desired signals are received and to suppress interference fromneighboring cells. Fast Rx beam refinement, in which the Rx beamdirection is dynamically adjusted in response to the channel conditionsmeasured by the UE, is desirable from a performance standpoint.

This may be particularly desirable with use of the high-frequency bandsaround, for example, 28 GHz, 37 GHz, 39 GHz, and 64-71 GHz, used inconjunction with carrier aggregation, which may permit networks tocontinue to service the never-ending hunger for data delivery. Theincreased beamforming gain in this frequency range may permit the UE andeNB to compensate for the increasingly likely event of severe pathlossand suppress mutual user interference, leading to an increase in systemcapacity and coverage.

To maximize the beamforming gain, as indicated above, the UE may searchfor an optimum Tx/Rx beam pair using the BRS. However, the BRS is abroadcast signal that is transmitted periodically on all Tx beams in afixed manner. This means that to detect the BRS, the UE may have to waituntil the next BRS subframe for Rx beam refinement if the UE has justmissed the BRS. This, however, may not be fast enough in somecircumstances. In addition to or instead of using the BRS, the CSI-RS orSounding RS (SRS) also can be utilized for Rx beam refinement. In thiscase, however, the Tx beams on the RS used are limited to the mostrecent reported BRS measurement. Thus, a BRRS may be produced fortransmission on the same Tx beam as data to be transmitted to the UE.

In some embodiments, to achieve faster Rx beam refinement and update theRx beam, a BRRS may be transmitted on the same Tx beam as data to betransmitted to the UE. The BRRS, along with the temporal proximityrelative to the data OFDM symbols (e.g., within 6, 13, or 25 ms),establishes an association between the BRRS and the data on the same Txbeam. Multiple BRRS symbols may be transmitted using the same Tx beam.Such Rx-beam refinement may enable the UE and eNB to use the selectedbeam to communicate more effectively. However, not all UEs may use BRRSsymbols. This may result in the BRRS symbols of one set of UEs and thedata symbols of another set of UEs causing mutual interference with eachother. To avoid the interference, BRRS symbol mapping and a specificBRRS format may be used.

Embodiments may be implemented in one or a combination of hardware,firmware, and software. Embodiments may also be implemented asinstructions stored on a computer-readable storage device, which may beread and executed by at least one processor to perform the operationsdescribed herein. A computer-readable storage device may include anynon-transitory mechanism for storing information in a form readable by amachine (e.g., a computer). For example, a computer-readable storagedevice may include read-only memory (ROM), RAM, magnetic disk storagemedia, optical storage media, flash-memory devices, and other storagedevices and media. Some embodiments may include one or more processorsand may be configured with instructions stored on a computer-readablestorage device.

Although an embodiment has been described with reference to specificexample embodiments, it will be evident that various modifications andchanges may be made to these embodiments without departing from thebroader scope of the present disclosure. Accordingly, the specificationand drawings are to be regarded in an illustrative rather than arestrictive sense. The accompanying drawings that form a part hereofshow, by way of illustration, and not of limitation, specificembodiments in which the subject matter may be practiced. Theembodiments illustrated are described in sufficient detail to enablethose skilled in the art to practice the teachings disclosed herein.Other embodiments may be utilized and derived therefrom, such thatstructural and logical substitutions and changes may be made withoutdeparting from the scope of this disclosure. This Detailed Description,therefore, is not to be taken in a limiting sense, and the scope ofvarious embodiments is defined only by the appended claims, along withthe full range of equivalents to which such claims are entitled.

Such embodiments of the subject matter may be referred to herein,individually and/or collectively, by the term “embodiments” merely forconvenience and without intending to voluntarily limit the scope of thisapplication to any single inventive concept if more than one is in factdisclosed. Thus, although specific embodiments have been illustrated anddescribed herein, it should be appreciated that any arrangementcalculated to achieve the same purpose may be substituted for thespecific embodiments shown. This disclosure is intended to cover any andall adaptations or variations of various embodiments. Combinations ofthe above embodiments, and other embodiments not specifically describedherein, will be apparent to those of skill in the art upon reviewing theabove description.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B.” unlessotherwise indicated. In this document, the terms “including” and “inwhich” are used as the plain-English equivalents of the respective terms“comprising” and “wherein.” Also, in the following claims, the terms“including” and “comprising” are open-ended: that is, a system, UE,article, composition, formulation, or process that includes elements inaddition to those listed after such a term in a claim are still deemedto fall within the scope of that claim. Moreover, in the followingclaims, the terms “first,” “second,” and “third.” etc. are used merelyas labels, and are not intended to impose numerical requirements ontheir objects.

The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b), requiring an abstract that will allow the reader to quicklyascertain the nature of the technical disclosure. It is submitted withthe understanding that it will not be used to interpret or limit thescope or meaning of the claims. In addition, in the foregoing DetailedDescription, it can be seen that various features are grouped togetherin a single embodiment for the purpose of streamlining the disclosure.This method of disclosure is not to be interpreted as reflecting anintention that the claimed embodiments require more features than areexpressly recited in each claim. Rather, as the following claimsreflect, inventive subject matter lies in less than all features of asingle disclosed embodiment. Thus the following claims are herebyincorporated into the Detailed Description, with each claim standing onits own as a separate embodiment.

What is claimed is:
 1. An apparatus, comprising: a memory; and aprocessor in communication with the memory and arranged to cause a userequipment (UE) for narrowband internet-of-Things (NB-IoT) communicationto: monitor signals on a first transmission bandwidth for a narrowbandsystem with the first transmission bandwidth comprising a singlephysical resource block bandwidth; blind decode one or more narrowbandphysical downlink control channel (NB-PDCCH) search space candidates byprocessing a first physical resource block of the first transmissionbandwidth and orthogonal frequency division multiplexed symbols of afirst subframe, wherein said blind decoding comprises attempting toblind decode one or more NB-PDCCH search space candidates of a pluralityof NB-PDCCH search space candidates, wherein each of the plurality ofNB-PDCCH search space candidates are defined using a pair of anaggregation level (AL) and a repetition level (RL) to monitor, whereinthe AL is defined as a number of narrowband control channel elementsused within a subframe for NB-PDCCH transmission and the RL is definedas a number of subframes over which the narrowband control channelelement(s) are repeated in a time dimension; and extract modulatedsymbols of a control channel transmission after successful blinddecoding of a first NB-PDCCH search space candidate.
 2. The apparatus ofclaim 1, wherein blind decoding the one or more NB-PDCCH search spacecandidates comprises processing a plurality of physical resource blocks,the plurality of physical resource blocks comprising the first physicalresource block, wherein each physical resource block of the plurality ofresource blocks comprises all subcarriers of the first transmissionbandwidth for corresponding time periods.
 3. The apparatus of claim 2,wherein the corresponding time periods for the plurality of physicalresource blocks are consecutive in the time dimension.
 4. The apparatusof claim 2, wherein the corresponding time periods for the plurality ofphysical resource blocks are not all consecutive in the time dimension.5. The apparatus of claim 2, wherein the processor is further configuredto cause the UE to extract modulated symbols of the one or morenarrowband control channel elements of the control channel transmissionaccording to the AL and the RL.
 6. The apparatus of claim 5, wherein asubcarrier of one orthogonal frequency division multiplexed symbolcomprises a resource element of a respective narrowband control channelelement of the one or more narrowband control channel elements.
 7. Theapparatus of claim 6, wherein the respective narrowband control channelelement comprises a first subcarrier of the first subframe.
 8. Theapparatus of claim 7, wherein the respective narrowband control channelelement further comprises modulated symbols of the control channeltransmission mapped to a direct current (DC) subcarrier of an orthogonalfrequency division multiplexing (OFDM) waveform.
 9. The apparatus ofclaim 7, wherein the respective narrowband control channel elementcomprises a set of subcarriers.
 10. The apparatus of claim 1, whereintwo narrowband control channel elements are defined within the subframe.11. The apparatus of claim 10, wherein the AL is either 1 or 2 for theNB-PDCCH search space candidates.
 12. The apparatus of claim 11, whereina maximum of two NB-PDCCH transmissions are multiplexed in the subframe.13. The apparatus of claim 1, further comprising: an antenna configuredto receive the signals on the first transmission bandwidth and transmitthe signals to the processor.
 14. A method for operating a userequipment (UE) for narrowband internet-of-Things (NB-IoT) communication,the method comprising: monitoring signals on a first transmissionbandwidth for a narrowband system with the first transmission bandwidthcomprising a single physical resource block bandwidth; blind decodingone or more narrowband physical downlink control channel (NB-PDCCH)search space candidates by processing a first physical resource block ofthe first transmission bandwidth and orthogonal frequency divisionmultiplexed symbols of a first subframe, wherein said blind decodingcomprises attempting to blind decode one or more NB-PDCCH search spacecandidates of a plurality of NB-PDCCH search space candidates, whereineach of the plurality of NB-PDCCH search space candidates are definedusing a pair of an aggregation level (AL) and a repetition level (RL) tomonitor, wherein the AL is defined as a number of narrowband controlchannel elements used within a subframe for NB-PDCCH transmission andthe RL is defined as a number of subframes over which the narrowbandcontrol channel element(s) are repeated in a time dimension; andextracting modulated symbols of a control channel transmission aftersuccessful blind decoding of a first NB-PDCCH search space candidate.15. The method of claim 14, wherein blind decoding the one or moreNB-PDCCH search space candidates comprises processing a plurality ofphysical resource blocks, the plurality of physical resource blockscomprising the first physical resource block, wherein each physicalresource block of the plurality of resource blocks comprises allsubcarriers of the first transmission bandwidth for corresponding timeperiods.
 16. The method of claim 15, the method further comprising:causing the UE to extract modulated symbols of one or more narrowbandcontrol channel elements of the control channel transmission accordingto the AL and the RL.
 17. An apparatus of a base station for encodingcontrol channel signals for narrowband Internet-of-Things (NB-IoT)communications, the apparatus comprising: a memory; and a processor incommunication with the memory and arranged to: encode a first controlchannel transmission using a first physical resource block of a firsttransmission bandwidth for a narrowband system and orthogonal frequencydivision multiplexed symbols of a first subframe; and transmit the firstcontrol channel transmission to a user equipment (UE) over a narrowbandphysical downlink control channel (NB-PDCCH), wherein the first controlchannel transmission comprises a first NB-PDCCH candidate for the UE toattempt to blind decode, wherein the NB-PDCCH candidate is selected froma plurality of NB-PDCCH candidates, wherein each of the plurality ofNB-PDCCH search space candidates are defined using a pair of anaggregation level (AL) and a repetition level (RL) for monitoring,wherein the AL is defined as a number of narrowband control channelelements used within a subframe for the first control channeltransmission and the RL is defined as a number of subframes over whichthe narrowband control channel element(s) are repeated in a timedimension.
 18. The apparatus of claim 17, wherein the processor isfurther configured to encode the first control transmission from thebase station to the UE using a plurality of physical resource blocks,the plurality of physical resource blocks comprising the first physicalresource block, wherein each physical resource block of the plurality ofresource blocks comprises all subcarriers of the first transmissionbandwidth for corresponding time periods.
 19. The apparatus of claim 18,wherein the corresponding time periods for the plurality of physicalresource blocks are not all consecutive in the time domain.
 20. Theapparatus of claim 17, wherein two narrowband control channel elementsare defined within the subframe.
 21. An apparatus, comprising: aprocessor arranged to cause a user equipment (UE) for narrowbandinternet-of-Things (NB-IoT) communication to: monitor signals on a firsttransmission bandwidth for a narrowband system with the firsttransmission bandwidth comprising a single physical resource blockbandwidth; blind decode one or more narrowband physical downlink controlchannel (NB-PDCCH) search space candidates by processing a firstphysical resource block of the first transmission bandwidth andorthogonal frequency division multiplexed symbols of a first subframe,wherein said blind decoding comprises attempting to blind decode one ormore NB-PDCCH search space candidates of a plurality of NB-PDCCH searchspace candidates, wherein each of the plurality of NB-PDCCH search spacecandidates are defined using a pair of an aggregation level (AL) and arepetition level (RL) to monitor, wherein the AL is defined as a numberof narrowband control channel elements used within a subframe forNB-PDCCH transmission and the RL is defined as a number of subframesover which the narrowband control channel element(s) are repeated in atime dimension; and extract modulated symbols of a control channeltransmission after successful blind decoding of a first NB-PDCCH searchspace candidate.
 22. The apparatus of claim 21, wherein blind decodingthe one or more NB-PDCCH search space candidates comprises processing aplurality of physical resource blocks, the plurality of physicalresource blocks comprising the first physical resource block, whereineach physical resource block of the plurality of resource blockscomprises all subcarriers of the first transmission bandwidth forcorresponding time periods.
 23. The apparatus of claim 22, wherein thecorresponding time periods for the plurality of physical resource blocksare consecutive in the time dimension.
 24. The apparatus of claim 22,wherein the corresponding time periods for the plurality of physicalresource blocks are not all consecutive in the time dimension.
 25. Theapparatus of claim 22, wherein the processor is further configured tocause the UE to extract modulated symbols of the one or more narrowbandcontrol channel elements of the control channel transmission accordingto the AL and the RL.
 26. The apparatus of claim 25, wherein asubcarrier of one orthogonal frequency division multiplexed symbolcomprises a resource element of a respective narrowband control channelelement of the one or more narrowband control channel elements.
 27. Theapparatus of claim 25, wherein the respective narrowband control channelelement comprises a first subcarrier of the first subframe.
 28. Theapparatus of claim 27, wherein the respective narrowband control channelelement further comprises modulated symbols of the control channeltransmission mapped to a direct current (DC) subcarrier of an orthogonalfrequency division multiplexing (OFDM) waveform.
 29. The apparatus ofclaim 27, wherein the respective narrowband control channel elementcomprises a set of subcarriers.
 30. The apparatus of claim 21, whereintwo narrowband control channel elements are defined within the subframe.31. The apparatus of claim 30, wherein the AL is either 1 or 2 for theNB-PDCCH search space candidates.
 32. The apparatus of claim 31, whereina maximum of two NB-PDCCH transmissions are multiplexed in the subframe.33. The apparatus of claim 21, further comprising: an antenna configuredto receive the signals on the first transmission bandwidth and transmitthe signals to the processor.
 34. An apparatus of a base station forencoding control channel signals for narrowband Internet-of-Things(NB-IoT) communications, the apparatus comprising: a processor arrangedto: encode a first control channel transmission using a first physicalresource block of a first transmission bandwidth for a narrowband systemand orthogonal frequency division multiplexed symbols of a firstsubframe; and transmit the first control channel transmission to a userequipment (UE) over a narrowband physical downlink control channel(NB-PDCCH), wherein the first control channel transmission comprises afirst NB-PDCCH candidate for the UE to attempt to blind decode, whereinthe NB-PDCCH candidate is selected from a plurality of NB-PDCCHcandidates, wherein each of the plurality of NB-PDCCH search spacecandidates are defined using a pair of an aggregation level (AL) and arepetition level (RL) for monitoring, wherein the AL is defined as anumber of narrowband control channel elements used within a subframe forthe first control channel transmission and the RL is defined as a numberof subframes over which the narrowband control channel element(s) arerepeated in a time dimension.
 35. The apparatus of claim 34, wherein theprocessor is further configured to encode the first control transmissionfrom the base station to the UE using a plurality of physical resourceblocks, the plurality of physical resource blocks comprising the firstphysical resource block, wherein each physical resource block of theplurality of resource blocks comprises all subcarriers of the firsttransmission bandwidth for corresponding time periods.
 36. The apparatusof claim 35, wherein the corresponding time periods for the plurality ofphysical resource blocks are not all consecutive in the time domain. 37.The apparatus of claim 34, wherein two narrowband control channelelements are defined within the subframe.